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CAMBRIDGE BIOLOGICAL SERIES, 



GENERAL EDITOR : ARTHUR E. SHIPLEY, M.A. 



FELLOW AND TUTOR OF CHRIST'S COLLEGE, CAMBRIDGE. 



. 



A TEXT-BOOK 



OF 



ZOOGEOGRAPHY 




HonDon: C. J. CLAY AND SONS, 



CAMBRIDGE UNIVERSITY PRESS WAREHOUSE, 



AVE MARIA LANE, 



AND 



H. K. LEWIS, 

 136, GOWER STREET, W.C. 



lasgoto: 50, WELLINGTON STREET. 

 ILetpjtg: F. A. BROCKHAUS. 

 orfc: THE MACMILLAN COMPANY. 

 ISomfeag anfc Calcutta: MACMILLAN AND CO., LTD. 



[All Rights reserved.] 






z 



A TEXT -BOOK 



OF 



ZOOGEOGRAPHY 



BY 



FRANK E. BEDDARD, M.A. (OxoN.), F.R.S. 



PROSECTOR OF THE ZOOLOGICAL SOCIETY OF LONDON, AND 

 LECTURER ON BIOLOGY AT GTJY's HOSPITAL. 



CAMBRIDGE : 



AT THE UNIVERSITY PEESS 



1895 




(JTambrttige : 



PRINTED BY J. AND C. F. CLAY 

 AT THE UNIVERSITY PRESS. 




PREFACE. 



TN this volume I have attempted to give the principal 

 -*- facts and conclusions of Zoogeography, without an 

 undue profusion of detail. A few examples only have 

 been selected to illustrate the principles. As far as 

 possible I have endeavoured to use instances that have 

 not been made use of by Mr Wallace in his two works 

 upon this subject. I have taken Kerguelen Island and 

 Fernando Noronha as examples of oceanic islands ; the 

 facts of distribution and the inferences to be drawn are 

 illustrated largely by the earthworms ; and in other 

 places I have availed myself of some of the more recent 

 sources of information. Naturally a large portion of this 

 book, as must be the case with any book upon Geographical 

 Distribution, is based upon the two indispensable treatises 

 of Mr Wallace. I have also found great assistance in 

 Prof. Heilprin's work upon Distribution in the Inter- 

 national Scientific Series, and in an excellent manual 




VI PREFACE. 



upon the same subject by M. Trouessart ; I have checked 

 and added to the facts that I had accumulated by a careful 

 comparison of them with the article Geographical Dis- 

 tribution in Prof. Newton's Dictionary of Birds. Numerous 

 special memoirs have also been laid under contribution, 

 a reference to which will be found in the proper place. 



FRANK E. BEDDARD. 



LONDON. 



November, 1894. 




CONTENTS. 

 CHAPTER I. 



THE GENERAL FACTS OF THE DISTRIBUTION OF ANIMALS. 



Introductory, p. 1. Locality and Station, 5. Cosmopolitan 

 groups, 8. Restricted groups, 10. The meaning of a restricted 

 distribution, 12. Discontinuous distribution, 15. Separate areas of 

 the species of a genus, 18. Distribution of Rhea, 19. Distribution 

 of Ibexes, 20. Distribution of the Cassowaries, 23. Classification 

 and Distribution, 25. Distribution of the Gallinaceous birds, 26. 

 Distribution of the Edentata, 31. Distribution of the Cuckoos, 35. 

 Distribution of Chelonia, 38. Distribution of Lizards, 40. Distribu- 

 tion of Crocodiles, 43. Distribution of Snakes, 46. Distribution of 

 Batrachia, 47. Distribution of Scorpions, 49. Distribution of Land 

 Planarians, 53. Distribution of Earthworms, 57. 



CHAPTER II. 



ZOOLOGICAL GEOGRAPHY. 



Mr Sclater's regions, 72. Mr Huxley's regions, 75. Other sug- 

 gested regions, 76. Mr Sclater's regions the most convenient, 78. 

 The six Zoological regions of Mr Sclater, 88. The Palsearctic 

 region, 88. The Nearctic region, 93. The Ethiopian region, 98. 

 The Oriental region, 102. The Neotropical region, 107. The 

 Australian region, 113. Some graphic methods of presenting the 

 facts of Distribution, 118. 



CHAPTER III. 



THE CAUSES WHICH INFLUENCE THE DISTRIBUTION 



OF ANIMALS. 



Distribution not dependent upon temperature, 124. Distribu- 

 tion of Crustacean Arcturus as illustrative of connection between 

 range and temperature, 125. The country inhabited by an animal 



37144 




Vlll CONTENTS. 



is not necessarily the only one in which it can flourish, 128. 

 Similarities in the faunas of distant countries, 129. Problems of 

 Distribution and Evolution, 131. Means of Dispersal of Animals, 

 134. The influence of geological terrain upon faunas, 136. Dispersal 

 of Oligochteta, 138. Dispersal of Mollusca, 140. Dispersal of 

 Amphibia, 145. Dispersal of Reptiles, 147. Evidence of capacity 

 for Migration on the part of a given animal, 150. Influence of 

 human interference upon Migration, 151. The existing Distribution 

 of land and sea considered in relation to Zoological Geography, 155. 

 Evidence in favour of Permanence of Oceans, 156. Evidence against 

 the view that existing Oceans have not largely changed their 

 areas, 159. Evidence in favour of a formerly more extensive 

 Antarctic Continent, 164. " Lemuria," 176. 



CHAPTER IV. 



THE FAUNA OF ISLANDS. 



The Fauna of the British Isles, 183. The Fauna of Madagascar, 

 187. The Fauna of Fernando Noronha, 190. The Fauna of 

 Kerguelen, 193. The Fauna of the Galapagos, 195. The Fauna of 

 New Zealand, 199. Fauna of the Sandwich Islands, 203. General 

 observations upon the Fauna of Islands, 204. Continental Islands, 

 205. Oceanic Islands, 207. Anomalous islands, 210. Some pecu- 

 liarities of island animals, 212. 



CHAPTER V. 



SOME THEORETICAL CONSIDERATIONS. 



The bearing of the facts of distribution upon the places of origin 

 of different groups, 220. The place of origin of the Marsupials, 222. 

 Theory of the Polar origin of Life, 227. 



Map shewing Zoogeographical Regions . . Frontispiece 



distribution of Edentata . . . to face p. 32 



Earthworms . . 65 



Struthious Birds 168 



Lemurs . 187 




CHAPTER I. 



THE GENERAL FACTS OF THE DISTRIBUTION OF ANIMALS. 



Introductory. 



THE entire world both land and sea supports every- 

 where animal life. The extreme cold of the arctic regions 

 is not too intense to permit of the existence of at least a 

 few forms of life, while the warmer regions of the globe 

 have everywhere an abundant fauna, which increases 

 towards the tropics ; it is even probable that the icebound 

 antarctic continent, if it could be explored, would be found 

 to possess some inhabitants. 



The most elementary knowledge of Zoology is sufficient 

 bo enable us to see that, while terrestrial life is as 

 abundant as marine, the kinds of animals inhabiting these 

 diverse situations are different. We can distinguish in 

 fact between purely terrestrial and purely aquatic animals. 

 The latter group can be again divided into two great 

 classes, those which inhabit the sea and those which 

 inhabit the fresh waters of the land. There is however 

 no absolute break between these various groups. The 



B. Z. 1 




2 TERRESTRIAL AND AQUATIC ANIMALS. [CH. I 



fresh waters themselves gradually pass into salt at the 

 mouths of rivers ; while a marsh, particularly one that is 

 subject to periodical drying up, is to some extent inter- 

 mediate between the land and the water. 



Corresponding to this absence of hard and fast lines in 

 inorganic nature we find a similar absence of definiteness 

 in the animals which frequent the waters, the dry land, 

 and the transitional areas. The duck tribe are equally at 

 home when swimming in a lake and when flying from one 

 pool to another. There are even ducks which perch on 

 trees. Closely allied Crustacea may be marine, estuarine, 

 fresh water or terrestrial in habit. Certain sharks, nor- 

 mally marine, ascend rivers for some distance, and the 

 Manatee of the west coast of Africa and the east coast of 

 America is quite as much at home when browsing upon 

 the marine algae of the coasts of those continents as when 

 living in their rivers. Though we may broadly separate 

 animals into terrestrial and aquatic, there is no large 

 group of animals which is exclusively terrestrial. Even 

 insects which approach nearest to this condition have 

 plenty of aquatic representatives ; there is even a peculiar 

 genus of bugs, Halobates, which inhabits the open sea far 

 from land. 



On the other hand, there are groups which are purely 

 aquatic, and even some which are only marine, being never 

 found in fresh water ; but these are few. Among Verte- 

 brates fishes are the only group which can be said to be 

 almost absolutely aquatic ; and here too there are some 

 slight exceptions. The well-known Climbing Perch, Anabas 

 scandens, can with impunity leave the streams which it 




. l] HABITATS OF ANIMALS. 3 



inhabits ; the mud fish of Africa and America has lungs 

 as well as gills, and can suffer with equanimity the drying 

 up of the rivers in which it lives. Eels are said to move 

 from one pool to another across the intervening grass. 

 The curious little fish Periophihalmus voluntarily leaves 

 the sea and hops along its margin on the look-out for the 

 Mollusc Onchidiiim upon which it largely feeds. Among 

 Invertebrates there are more purely aquatic groups ; and 

 these are exclusively marine. No Ascidian, no starfish, 

 brittle star, sea urchin, or sea lily has as yet been met 

 with except in the sea. Sponges and Coelenterates are 

 Avithout exception aquatic and for the most part marine, 

 their delicate organisation not being able to withstand 

 continued dryness. But these are positively the only large 

 groups which are purely aquatic. Many others are prin- 

 cipally aquatic, such as the Flat worms, with terrestrial 

 allies in the land Planarians, the Crustacea, the Annelids 

 and some others. 



Not only can we draw these broad distinctions between 

 the habitats of different animals, finding one to be terres- 

 trial, another aquatic and a third amphibious ; we can also 

 assign to each a definite place upon the land or in the 

 waters. The Indian Ocean is frequented by creatures 

 which are unknown in the colder waters of the North Sea ; 

 the Mississippi has alligators which the Thames, for ex- 

 ample, has not. It is a matter of common knowledge that 

 the tiger is restricted to Asia and the puma to South and 

 certain parts of North America ; the elephant is unknown 

 beyond the old world, and it has even there a limited area 

 of range. It would be as surprising to meet with an 



12 




4 DISTRIBUTION OF LAND ANIMALS. [CH. I 



elephant even in the most secluded of Brazilian forests as 

 to meet with a tiger genuinely at home in the neighbour- 

 hood of a peaceful English village. 



That branch of Biology which is termed Geographical 

 Distribution, or, when applied to either animals or plants 

 only, Zoogeography and Phytogeography, is concerned 

 with facts such as the above ; it has also to do with the 

 solution or attempted solution of the various problems to 

 which these facts give rise. The science is not limited to 

 a consideration of the animals which inhabit dry land. 

 But this volume will only deal with those forms, touching 

 incidentally upon some of the fresh water species, whose 

 distribution is apparently governed by the same laws as 

 those which govern the distribution of the purely terres- 

 trial animals. 



We shall now commence our survey of the chief facts 

 in the distribution of land animals. It has been said that 

 every animal has its place in the world, which may be 

 wider or narrower. The country which is inhabited by a 

 given animal is called its area of distribution, its habitat 

 or locality. The converse follows that every tract of the 

 earth's surface is inhabited each by its peculiar set of 

 animals. But they are not met with everywhere in that 

 area. Almost every year a new volume is published 

 giving a list of the birds of a particular county or it may 

 be district ; anyone who will take the trouble to inspect 

 and compare a series of these volumes dealing with man} 

 different counties will be struck by the fact that a given 

 species of bird may be absent from one list or stated to be 

 uncommon, while numerous records of its discovery will be 




CH. l] LOCALITY AND STATION. 5 



found in another. The same thing holds true of other 

 groups ; the badger, for example, will be found in one wood 

 but will be absent from another ; nevertheless generally 

 speaking this animal may be said to inhabit the greater 

 part of England, not to mention foreign regions in which 

 it is also found. Were we to put together all that has 

 been recorded of the range of this or any other animal 

 and colour a map of England in correspondence with those 

 facts, we should find that a large map would be coloured 

 by a series of closely set but separate patches of colour ; 

 on the other hand a small map would practically have to 

 be coloured all over to indicate the range of the animal. 

 The reason for this is that the badger can only live in 

 certain kinds of country. It is not at home for instance 

 in bare chalky downs or on the tops of high mountains ; it 

 prefers woods and the immediate neighbourhood of woods. 



Locality and Station. 



We must carefully distinguish between locality and 

 station. While the area inhabited by a species is usually 

 continuous, it by no means always happens that the station 

 consists of one continuous tract. Animals inhabiting 

 forests or moorland or pools are only found where the 

 suitable circumstances occur. But in such instances the 

 habitat of the animal may be wide, only broken up into a 

 series of stations. We should not regard a case of this 

 kind as one of discontinuous distribution. Often however 

 the local phenomena of distribution have not so clear an 

 interpretation. Every entomologist is aware of the often 




6 RANGE OF LEPIDOPTERA. [CH. I 



capricious occurrence of butterflies and moths ; we do not 

 now refer to marsh-loving or wood-loving species or to any 

 intelligible restriction of this kind. Out of a dozen fields, 

 to the eye equally well suited for the maintenance of a 

 given species of moth, in which for instance the food plant 

 is equally abundant, two or three or it may be only one 

 will be inhabited by the insect in question, which will 

 there perhaps swarm. Some years since a small moth was 

 found at Folkestone only in a particular tract of grass 

 with no obvious advantages indeed the reverse, as it was 

 scanty and trodden under the feet of passers by to the 

 exclusion of neighbouring grassy areas ; this insect, known 

 as Tapinostola bondii, was abundant in this particular 

 locality but nowhere else in the neighbourhood. In every 

 local faunal list such and such a wood or field is given as 

 the locality for a particular insect, which would be equally 

 at home in other woods and fields, but is not as a matter 

 of fact found in them. To get the particular insect we 

 have perhaps to journey to another county or even to 

 another part of England ; possibly a particular wood is 

 the only part of England where it is to be met with and 

 the next locality will be on the Continent. No doubt 

 some of these apparently capricious variations are to be 

 explained by advancing civilisation. Building, draining 

 and the gradual reclamation of the country are fatal to 

 insect life as a rule. But this will not explain every case 

 of capricious restriction to a few r separated stations, such 

 as are so commonly met with among the Lepidoptera of 

 this country. 




CH. l] WIDE RANGE OF CERTAIN FORMS. 7 



The Range of Animals. 



In the range of species we meet with every condition, 

 from world-wide distribution to the most restricted habitat. 

 It has been said that man is the only animal (with the 

 exception perhaps of his parasites) which is literally found 

 in every habitable part of the earth's surface ; but a few 

 others are almost as widely scattered. Among mammals 

 only certain bats are in this position, for though the 

 common mouse and the rat are found nearly everywhere, 

 it is very possible that man is responsible for this wide 

 dissemination. The Barn Owl (Strix flammea) occurs in 

 most parts both of the new and old worlds. It is true 

 that in different countries it has received different names ; 

 but the opinion of many is that these are at the most 

 local races which are hardly deserving of being separated 

 as species. The Painted Lady (Vanessa cardui) is an 

 example from another class of animals which has an 

 equally wide range. This butterfly extends from Europe 

 to the Islands of the Pacific and to New Zealand, but is 

 not found in the West Indies and certain parts of South 

 America. The common Red river Worm (Tubifex) seems 

 to be universally spread. At any rate examples from so 

 distant a spot as New Zealand do not differ in any 

 appreciable point from those of England. A species be- 

 longing to another family of Oligochseta, Henlea ventri- 

 culosa, occurs in Europe, in the territory of the Khirghese 

 Tartars, and in New Zealand. 



The now extinct Large Copper Butterfly was formerly 

 found in abundance in the Cambridgeshire fens, but found 




8 ANIMALS WITH RESTRICTED RANGE. [CH. t 



nowhere else in the world. The limitation of particular 

 species of humming-birds to particular peaks of the Andes, 

 and of snails to particular valleys, are other examples. 

 Francolinus Kirki of the island of Zanzibar is almost as 

 striking an instance of the same phenomenon. The Ven- 

 dace (Coreyonus vandesius) restricted to Loch Maben in 

 Dumfriesshire is an animal with a still more limited range, 

 and several other examples might be given, particularly 

 from the faunas of islands. The two extremes are natu- 

 rally connected by numerous intermediate stages, where an 

 animal has a more or less limited habitat. 



Cosmopolitan groups. 



There are comparatively few groups of terrestrial 

 animals which are truly cosmopolitan. As the groups 

 get smaller the number of those that are cosmopolitan 

 decreases. That is to say, there are more cosmopolitan 

 families than genera, and more genera that are cosmo- 

 politan than species. 



Mr Wallace enumerates in his work upon Geographical 

 Distribution no less than sixteen families of birds which 

 are really cosmopolites ; they are, Corvidcs (Crows) and 

 Hirundinidce (Swallows) among Passerines; Kingfishers 

 among Picariae ; among other land birds, Columbidce 

 (Doves), Tetraonidce (Grouse), Falconidce (Hawks), Stri- 

 gidce (Owls) ; among waders Rallidce (Rails), Scolopacidce 

 (Snipe), Charadrice (Plovers), Ardeidw (Herons); among 

 aquatic birds Anatidce (Ducks and Geese), Laridce (Gulls), 

 Procellaridce (Petrels), Pelecanidce (Pelicans) and Podici- 




CH. l] COSMOPOLITAN GENERA. 9 



pedidce (Grebes). Only one family of mammals are really 

 cosmopolitan, namely, the Vespertilionidce. There are 

 several families of butterflies and moths which are in 

 this position and nearly all the families of beetles. The 

 Helwidce alone of the terrestrial Mollusca are universally 

 distributed, and among earthworms the two families Lum- 

 bricidce and Cryptodrilidce. It is a significant fact that of 

 these families by far the majority are winged creatures, 

 which are naturally less restricted by barriers. The earth- 

 worms form an apparent exception which is not really so ; 

 for it is highly probable that the universal range of these 

 families is due to human agency. Again, it is important 

 to notice that of the cosmopolitan birds at least eight are 

 largely aquatic in habit or frequent the margins of streams 

 and lakes. The conditions of life for aquatic birds are 

 more similar in different parts of the globe than those 

 of purely land birds. Moreover all these families are 

 numerous in genera and species. 



Cosmopolitan genera are fewer in proportion. Among 

 birds we have Hirundo (Swallow), Pandion (Osprey), Strix 

 (Barn Owl), Rallus, Porzana (Rails), Gallinula, Fulica 

 (Coots), Numenius (Stilt Plovers), Limosa (God wits) and 

 several other Scolopacidse, Charadrius (Plovers), Ardea 

 (Heron), Nycticorax (Xight-heron), A-nas (Duck), Stereo- 

 rarius (Skua), Larus (Gull), Sterna (Tern), Puffinus (Puffin), 

 Procellaria, Fulmarus (Petrels), Pelecanus (Pelican), Pha- 

 lacrocorax (Cormorant), Podicipes (Grebe). Among butter- 

 flies the genera Pyrameis (Painted Lady), Polyommatus 

 (Blues), Pieris (Whites), Papilio (Swallowtail), Pamphila 

 and Hesperia (Skippers) are universally distributed. 




10 COSMOPOLITAN SPECIES. [CH. I 



Macroglossa, Chcerocampa (Hawkmoths), Macrosila (Clear 

 wing) among moths are also cosmopolitan. 



As to species there are comparatively few that have a 

 world- wide range ; the most striking example among birds 

 is the Osprey. Gallinula chloropus and Totanus incanus 

 have the same distribution. Among insects it is more 

 difficult to discount the interference of man, which may 

 be responsible for a world- wide distribution. Anosia 

 plexippus is a butterfly which appears to be found almost 

 everywhere. I have dealt on another page 1 with those 

 species of earthworms which are cosmopolitan or nearly 

 so and arrived at the conclusion that it is in those cases 

 really a question of transport by man. The same argu- 

 ment seems according to M. Trouessart to apply to the 

 cosmopolitan Gecko, Platydactylus facetanus. Even the 

 Lepidoptera above mentioned are not above suspicion 

 on this score ; the pupae could so easily be accidentally 

 conveyed to the most distant countries. The common 

 bee-fly (Eristalis tenax), which so closely resembles to 

 the superficial inspection a honey-bee, has reached as far 

 as New Zealand, doubtless by the same agency. 



Restricted groups. 



We have besides universally distributed groups some: 

 of which are remarkably limited in their range. Naturally 

 this applies most of all to species and least to families. 

 The majority of species have a more or less restricted 

 range, so much so that it would be impossible to give any 



1 v. infra. 




CH. l] GENERA AND SPECIES OF LIMITED RANGE. 11 



catalogue of them. A few of the more remarkable ex- 

 amples may however be referred to. The most striking of 

 these are certain fishes which are limited to a single lake ; 

 thus the Lough Killin Charr is confined to the lake of 

 that name. A small moth, Ornix devomella, was once only 

 found in Devonshire. The monkeys of the genus Brachy- 

 urus, comprising three species, are limited each to a 

 moderately small forest tract in South America. The 

 majority of examples of species with a limited range 

 are of course to be found upon oceanic islands. Not 

 only are there species with a very small range in space 

 but also genera. Here again the most numerous examples 

 are to be found on oceanic islands such as the now extinct 

 Starling, Fregilupus, of Reunion. But there are other 

 cases of genera which have facilities for a wider range, 

 but which for one reason or another (to be considered 

 later) have been unable to extend that range. The genus 

 Opisthocomus (containing by the way only a single species, 

 being the type of a distinct family) is limited to a portion 

 of British Guiana ; the Gorilla to the forest tract of the 

 west coast of Africa ; here again there is but one species. 

 Among families there are also a few with an exceedingly 

 restricted distribution. The Rhinochetidse, containing only 

 one genus and species, R. jubatus, the Kagu, is only found 

 in the island of New Caledonia; the Trumpeters or 

 Psophiidse are confined to certain districts of the Amazons, 

 and the four or five species of the genus might be quoted 

 as a case of very limited range in species. In Madagascar 

 the family Chiromyidae is represented by but one species. 

 Cases of limited range among groups that may be regarded 




12 DISTRIBUTION OF MONOTREMATA. [CH. I 



as higher than families are naturally not common. The 

 most striking perhaps is that of the Rhynchocephalia ; this 

 group has but one species, the well-known Hatteria, which 

 is only found in a few small islands off the coast of New 

 Zealand. Not quite so striking from some points of view, 

 but perhaps more so in another, in that the group is a 

 higher one, is the case of the Monotremata; the two or 

 three genera are limited to certain parts of the Australian 

 region. 



The facts just enumerated lead us to one of the 

 axioms of the science of Zoogeography, which was for- 

 mulated by Mr Sclater 1 in the following words. " Every 

 species occupies a definite area on the world's surface ; 

 and in like manner every genus and family, or other 

 higher assemblage of species, occupies a definite area on 

 the earth's surface ; or more shortly, locality or existence in 

 a certain spot is quite as much an attribute of animals as 

 structure or the possession of a certain form or shape." 



The meaning of a restricted distribution. 



It does not, however, by any means follow that this 

 area is now as it always has been. To study Zoogeography 

 properly a knowledge of the extinct forms of life is not 

 only desirable but necessary. By the aid of Palaeontology 

 various facts, at first sight dark and meaningless, become 

 clear, or at least clearer. We must imagine each species 

 setting out from its centre of origin and gradually ex- 



1 "The Geographical Distribution of Mammals," Manchester Science 

 Lectures, 1875. 




CH. l] AREA INHABITED BY CHIMPANZEE. 13 



tending itself by actual or passive migration right and left 

 and in every possible direction from this focus. Gradually 

 the form will be modified, or by competition or for some 

 other reason become extinct, leaving perhaps descendants 

 scattered here and there to tell the tale of a formerly wide 

 range. A guess can be made as to the comparative age of 

 a species or a genus by comparing such facts. 



In all probability these instances of a restricted distri- 

 bution are to be explained in one of two ways ; either the 

 form is a new one or it is an ancient one. A new species 

 recently come into existence would naturally, at least on 

 any theory of evolution, have a limited range because it 

 would have come into being at one locality and not have 

 had time to extend its range, supposing an extension to 

 be possible and not barred by impassable barriers. 



The former alternative applies probably to most of the 

 examples that have been used, particularly perhaps to the 

 peculiar species often found upon oceanic islands. There 

 are however numerous species, as limited in their range, 

 which are in some cases certainly vestiges of races once 

 universally or widely distributed. 



The Chimpanzee tribe is at present limited to the 

 forest region of central Africa. Its utmost range is nearly 

 across that continent. But the palseontological records of 

 India contain a description and figures of a portion of a 

 skull evidently belonging to a chimpanzee which at one 

 time existed in India. Probably that indicated the high- 

 water mark of the extension of the chimpanzee, which has 

 since retired to more restricted boundaries. We know 

 from historical records that the lion used to occur in 




14 SIGNIFICANCE OF LIMITED AREAS. [CH. 1 



Greece as well as in India and Africa, where it is now alone 

 met with. And at an earlier period still it was found in 

 this country. The hippopotamus, now limited to Africa, 

 was once found in Madagascar, and probably the same 

 -species in Europe. 



In such cases however the species in question are 

 generally also of generic, even of family, rank. The 

 remarkable lizard Hatteria, as already mentioned, is con- 

 fined to one or two islands off New Zealand ; this lizard, 

 as the fossil remains of its allies tell us, is the sole survivor 

 of the Rhynchocephalia, a race of Saurians found in the 

 Mesozoic rocks of this country. The Viverrine Carnivore 

 Cryptopr octet, found at present only in Madagascar, is held 

 by some to be the last surviving remnant of the extinct 

 Creodonta ; in am^ case it is generically distinct from any 

 other carnivorous animal. The same arguments may be 

 applied to the Thylacine of Tasmania, to the Aye-Aye 

 (Chiromys) of Madagascar, and to many other animals. 

 An apparently similar series of facts is therefore probably 

 to be explained in quite a different manner, an instance 

 of extremes meeting. The same mode of distribution 

 is indicative either of great antiquity or of extreme 

 modernity. 



A comparatively restricted range however may be also 

 due to incapacity for migration. The converse is perhaps 

 more obvious. Widely distributed animals are either 

 flying animals independent of barriers which impede the 

 purely terrestrial species, or possess some special facilities 

 for voluntary or involuntary translation from country to 

 country. An entirely arboreal creature cannot pass across 




CH. l] DISCONTINUOUS DISTRIBUTION. 15 



a level tract of country with no trees ; nor can an 

 Amphibian whose skin requires to be kept moist cross an 

 arid desert. This consideration leads to an important 

 matter, the capacities for migration possessed by different 

 animals which will be discussed later. 



Discontinuous distribution. 



On the hypothesis that each animal has had its centre 

 of dispersal, that it came into existence once and at a 

 definite place, it is clear that originally at least the area 

 inhabited by a given species must have been perfectly 

 continuous. As a matter of fact it is generally the case ; 

 the remarkable thing appears to be not that there are 

 occasionally breaks in the continuity of the area inhabited 

 by a certain species but that it is so difficult to find 

 instances to illustrate the breaks. Mr Wallace explains 

 the rarity of discontinuous distribution among the species 

 of birds by the suggestion that they are possibly " more 

 rapidly influenced by changed conditions, so that when a 

 species is divided the two portions almost always become 

 modified into varieties or distinct species." It must be 

 borne in mind also that birds are a modern group, and the 

 very difficulty of classifying them satisfactorily indicates 

 that there are but few breaks in the series ; they are 

 possibly still in a condition of perpetual modification ; 

 they have not so to speak become fixed and crystallised, 

 like some of the older and in a sense more effete groups of 

 animals. However this may be, Mr Wallace quotes from 

 Mr Seebohm a highly remarkable instance of discontinuous 




16 RANGE OF GENUS PERIPATUS. [CH. I 



distribution in a species of Tit. The Marsh tit, Parus 

 palustris, has a range nearly co-extensive with the 

 Palsearctic region ; but it is known throughout this 

 immense tract of country in certainly three varieties. 

 One of these is found in Southern Europe, in Italy, 

 Turkey, Greece, and Asia Minor. The same variety does 

 not crop up in the intervening country but again appears 

 in South China. Whether this variety is entitled to 

 specific rank or not, the fact is remarkable and really of 

 equal value. It almost suggests an explanation that has 

 been sometimes advanced to account for discontinuous 

 distribution in the species of Mollusca. No great diffi- 

 culty could be felt in the assumption that the same 

 variety had been twice produced in localities of a somewhat 

 similar climate. Mr Wallace refers to one or two other 

 examples of a somewhat similar nature ; the Reed bunting 

 of this country reappears in Japan, being absent from 

 Asia. To take an instance from another class, Dr Scudder 

 records the existence of the butterfly CEneis jutta 1 in the 

 Rocky Mountains of British Columbia and in Hudson's 

 Bay, and its absence from the intervening tract. 



The genus Peripatus^ offers an example of a genus 

 with an exceedingly wide and at the same time discon- 

 tinuous distribution. Peripatus is universally regarded 

 as a very archaic form of Arthropod, which has preserved 

 certain characters of the worm-like ancestor from which it 

 is presumed that the Arthropods have been derived. 

 There are, for example, a series of paired excretory organs 



1 Butterflies of E. United States. 



2 Quart. Journ. Micr. Sci. vol. 28, 1888. 




CH. l] RANGE OF PERIPATUS. 17 



like those that occur among the segmented worms. On 

 the other hand it has the tracheae of the tracheate 

 division of the Arthropods, and at least rudimentary 

 appendages of the Arthropod type. The genus has been 

 recently the subject of a careful monograph, so that we 

 are in possession of the facts of structure and distribution 

 of a good many species. Mr Sedgwick allows eleven 

 species as well founded, and there may be others. The 

 genus occurs in South Africa, South America and the 

 West Indies, in New Zealand and in Australia; one 

 specimen is found in Sumatra ; otherwise it is absent from 

 the Oriental region. The species of the genus are mainly 

 distinguished from each other by the position of the 

 generative aperture, by the number and structure of the 

 legs and by colour. Mr Sedgwick divides them into four 

 groups which correspond to their range ; the Australasian 

 species, for instance, form one group, the neotropical 

 another, and so forth. These four main groups are largely 

 separable on account of the varying position of the 

 generative pore, which may be between the last or the 

 penultimate pair of limbs or altogether at the end of the 

 body. There are differences too in the structure of the 

 generative organs, and the eggs show characteristic 

 variations; thus, in the Australasian species the ova are 

 large and full of yolk, in the Cape species though the ova 

 are large the yolk is not abundant, and finally in the 

 neotropical species of Peripatus the ova are quite minute, 

 and without food yolk. The single known species from 

 the Oriental region is more imperfectly known than many 

 of the others ; but it seems to resemble the neotropical 



B. z. 2 




18 DISTRIBUTION OF JAYS. [CH. I 



rather than the Ethiopian species, which is not a little 

 remarkable. It has, as have the neotropical forms, the 

 generative openings between the legs of the penultimate 

 pair. 



Separate areas of the species of a genus. 



It sometimes happens that the area of distribution of 

 a genus is perfectly continuous but traversed by large 

 rivers or other checks to distribution. A genus occupying 

 a group of islands, for example, may be said to have an 

 unbroken range so far as is possible ; but here under 

 similar circumstances it is frequently the case that the 

 isolation has been accompanied by the breaking up of the 

 genus into a number of species, perhaps corresponding 

 with the subdivisions of the area. The islands of the 

 group which together constitute the Sandwich Islands are 

 often inhabited by particular species belonging to a genus 

 common to the whole archipelago ; the huge tortoises of 

 the Galapagos are in the same condition. A large tract 

 of country is often similarly inhabited by a series of 

 species belonging to the same genus ; but each of these 

 keeps rigidly to its own particular territory : an inter- 

 mingling is rendered difficult perhaps by the infertility of 

 the species with each other, and partly also by the fact 

 that, the ground being already taken up, there is no room 

 for the inroad of a closely allied form, which has presumably 

 the same or nearly the same mode of life and would 

 therefore seriously compete. The twelve species of Jays 

 belonging to the genus Garrulus range over the greater 

 part of the Palsearctic region ; but nearly every species 




CH. l] DISTRIBUTION OF RHEA. 19 



has its own particular habitat, and does not interfere with 

 its neighbours. In the map which Mr Wallace gives in 

 illustration of the facts of distribution of this genus it is 

 seen that two species overlap just at the confines of 

 Europe and Asia, while the former of these, the European 

 Garrulus glandarius, is also overlapped by one species in 

 the south-east of Europe and by another in Algeria. It 

 is far more usual for species to occupy in common a given 

 area, than for a division of the territory to have taken 

 place. Nevertheless the example just quoted is by no 

 means unique, even among birds whose powers of flight 

 set ordinary barriers at defiance. But a rigid partition of 

 the area of a genus is more commonly met with among 

 animals which have not these exceptional means of 

 disposal. This will now r be illustrated by three examples. 



Distribution of Rhea. 



The distribution of the species of Rhea 1 illustrates the 

 limitation of the species of the same genus each to its 

 own particular tract. The genus itself occupies a con- 

 siderable area of S. America, to which continent it is 

 absolutely confined. The three species of the genus have 

 been lately subjected to a careful comparison by Dr 

 Gadow, who has plainly differentiated the three recognised 

 species, viz. Rh. americana, Rh. macrorhyncha and Rh. 

 darwini. The anatomical characters which distinguish 

 them are not of course very marked, but they are amply 



1 See Gadow, "Ou the Anatomical Differences in the three species of 

 Rhea," P.Z.S. 1885, p. 308. 



22 




20 THE SPECIES OF RHEA. [CH. I 



sufficient for the purpose. Rh. darwini and Rh. americana 

 agree to differ from Rh. macrorhyncha in having only 15 

 (instead of 16) cervical vertebrae and in having a broad 

 skull. They differ from each other principally in the fact 

 that the metatarsus in front has scutes on distal half only 

 in Rh. darwini; Rh. macrorhyncha agreeing with Rh. 

 > americana in having transverse scutes along the whole 

 length of that part of the leg in front. 



The range of the three is as follows : Rh. americana 

 extends from Bolivia through Paraguay into Uruguay 

 and southward to the Rio Negro. Its head-quarters seem 

 to be the pampas of Argentina. 



Rh. darwini is restricted to the eastern half of 

 Patagonia and to south-eastern Argentina. It overlaps 

 the last species about the Rio Negro. 



Finally Rh. macrorhyncha occurs in the provinces of 

 Pernambuco and Bahia but does not overlap Rh. americana. 

 Dr Gadow intimates that on the whole Rh. darwini is the 

 best marked species. Hence possibly its overlapping is 

 less remarkable, since the greater difference in organisation 

 may go with a greater difference in habits. 



Distribution of Ibexes. 



There are altogether eleven species of Wild Goats as 



allowed by Mr Sclater 1 , to which may be added a twelfth*. 



(1) Capra pyrenaica, the Spanish Ibex, is not only 



Pyrenean, but is found, slightly altered in character, in the 



mountain ranges of other parts of Spain and Portugal. 



1 P.z.s. 1886, p. 314. 



2 There are probably however more names than species. 




CH. I] RANGE OF WILD GOATS. 21 



" It is curious," remarks Mr Sclater, " that it is more 

 nearly allied to the Caucasian ibex than to the ibex of 

 the Alps." 



(2) C. ibex, the ibex or steinbok found in the Alps 

 and Tyrol, but rare and needing artificial preservation. 



(3) C. tugagrus, the true wild goat, is probably the 

 origin of the domestic variety. It is now found only in 

 Crete and some of the smaller Cyclades as regards 

 Europe, but also extends through Asia Minor and Persia 

 to Sind and Baluchistan. 



(4), (5) C. caucasica and C. pallasii are restricted to 

 the Caucasus, where they do not appear to overlap 

 greatly. 



(6) C. sinaitica. This ibex is found only in the 

 mountain ranges of Upper Egypt, the Sinaitic peninsula 

 and Palestine. 



(7) C. walie is a distinct though rare and little 

 known species, from the highest mountain ranges of 

 Abyssinia. 



(8) C. sibirica. It is remarkable that this species 

 should occur in two such distant localities as the Altai 

 mountains and the Himalayas. But it appears that a 

 thoroughly careful comparison of examples from the two 

 localities has not yet been made. This may very possibly 

 reveal differences. 



(9) C.falconeri. This ibex is popularly known as 

 the Markhore, it lives in the Pir-panjab and Sulaiman 

 ranges in Cashmere and Afghanistan. 



(10) C. jemlanica. The " Tahr " occurs along the 

 whole range of the Himalayas. 




22 WIDE DISTRIBUTION OF BEARS. [CH. I 



(11) C. hylocrius. This species of wild goat is 

 found in the Neilgherries and some other ranges of 

 southern India. 



(12) C. severtzowi. This is another Caucasian 

 ibex which Dr Menzbier has added to the two already 

 referred to. 



Here we have an instance of a genus of tolerably wide 

 distribution, but discontinuous. The discontinuity is 

 entirely due to the mode of life of the genus, which 

 frequents high mountains and cannot tolerate the level 

 plain. The mountains are comparable to oceanic islands 

 which can only be reached from time to time and under 

 favourable circumstances. This naturally results in the 

 isolation of those individuals which have migrated from 

 their original home to a neighbouring mountain range ; 

 and as a consequence of this isolation, which precludes 

 admixture with the parent stock, we have the production 

 of new forms, just as in the case of oceanic islands. With 

 this may be compared the distribution of such a genus as 

 the giraffe, which has, or had until very recently, a range 

 of nearly the same extent as measured by miles. But 

 this range is uninterrupted by many tracts of country 

 that are uninhabitable to the animal ; hence there are at 

 most two forms of giraffe. Even the true bears (genus 

 Ursus) may be contrasted. Dr Greve allows nine species 

 and five varieties, hardly more than there are of goats. 

 But the range is enormously larger nearly the whole 

 of Asia and Europe and nearly the whole of America 

 and there is nowhere a gap of any kind. 




CH. l] SPECIES OF CASSOWARY. 23 



Distribution of the Cassowaries. 



The species of the genus Casuarius present an ex- 

 cellent instance of the specialisation of a genus when its 

 region is broken up by barriers into detached areas. 

 There appear to be altogether eleven or twelve species 

 of cassowary that are well ascertained ; there may even 

 be one or two more ; at any rate there are more than 

 twelve names distributed among the cassowaries. I shall 

 not enter into the characters which distinguish the 

 species beyond remarking that they can be readily defined 

 by the shape of the " casque," by the presence or absence 

 of wattles depending from the patch of naked skin upon 

 the throat and by the particular tints exhibited by the 

 generally brilliant colouration of the latter. The casso- 

 waries are entirely limited in their distribution to the 

 Australian region and do not range over the whole of that 

 region. They are absent from New Zealand and from 

 many other outlying islands. But although the cas- 

 sowaries are of bulky form and like other Struthious birds, 

 quite incapable of flight, they are by no means limited to 

 the continent of Australia itself. The following is a list 

 of the properly defined species and their range : 



Casuarius australis, Australia. 



C. picticollis, 

 C. Edwardsi, 



C. W ester manni, 



C. uniappendiculatus, 



C. Salvadorii, 



C. galeatus, Ceram. 



New Guinea. 




24 CASSOWARIES OF NEW GUINEA. [CH. I 



C. Beccarii, Wokan. 

 C. bicarunculatus, Aru_ 

 C. Bennetti, New Britain. 



C. laqlaizei 1 , } 



J . .. j. \ Jobi. 



6. occipitalis,} 



This case is analogous in many ways to that of the 

 goats already dealt with. Isolation has led to the 

 differentiation of species from a presumably identical 

 stock. Furthermore, where the area is large it has proved 

 capable of sustaining several species, which is not the case 

 with those islands of limited extent, such as Ceram, which 

 harbour cassowaries. With this fact may be compared 

 the presence of only a single species of Ibex in the com- 

 paratively small tract of country occupied by the 

 Pyrenees, and the presence of this species in the more 

 extensive Caucasus. The existence of five out of the ten 

 species in New Guinea marks this large island out as the 

 head-quarters of the group from whence they have 

 migrated elsewhere, or perhaps, if the islands are to be 

 regarded as a broken continent, have been isolated. 

 That New Guinea is to be regarded as the original home 

 of the cassowaries is perhaps also shown by the fact that 

 the species now existing there present in themselves most 

 of the important modifications of structure which the 

 genus exhibits. In his most recent revision of the 

 cassowaries Mr Sclater divides those without wattles 

 from those which have these appendages. Both kinds 

 occur in New Guinea. On the other hand this con- 



1 The editor of the Ibis (Oct. 1894, p. 560) is inclined to doubt the 

 distinctness of these two species. 




CH. l] DISTRIBUTION AND STRUCTURE. 25 



sideration is to be qualified by the fact that no casso- 

 wary with a laterally compressed casque (another 

 character made use of by Mr Sclater) exists in New 

 Guinea. In all the New Guinea species the casque is 

 transversely compressed. 



Classification and Distribution. 



The facts of distribution are constantly liable to be 

 misunderstood through ignorance of classification. Not 

 only is a serious error in the actual facts of the distribution 

 of a particular group caused by wrongly assigning to it 

 some individual genus or species, but the significance 

 of the facts is by this largely, sometimes totally, obscured. 

 A knowledge of comparative anatomy is absolutely 

 essential to the student of distribution. It used to be 

 supposed that the central American Carnivore Bassaris 

 was a member of the family Viverridse ; the genus 

 therefore was believed to be the only Viverrine found in 

 the New World, a singular anomaly in the distribution of 

 the group. But Sir William Flower in his paper upon 

 the skull in the Carnivora showed that this animal is 

 really an ally of the Raccoons, which are purely an 

 American family. Everybody is acquainted with the 

 fact that monkeys are found both in the old world and in 

 the new. But the fact gets a far larger significance when 

 it is realised that the new world monkeys form a group 

 by themselves which differs from that of the old world 

 monkeys in a number of important anatomical characters. 

 The wide distance and the absence of means of transit 




26 WIDE RANGE OF ANCIENT FORMS. [CH. I 



within recent times has brought about the great diver- 

 gence which is now seen between the two sections of the 

 Primates, the new world Platyrrhines and the old world 

 Catarrhines. It has been already pointed out in dealing 

 with the distribution of the archaic Peripatus that the 

 species of different parts of the world form natural 

 assemblages separable from those of other parts of the 

 world by definite anatomical characters. This is the case 

 too with many other genera and families of animals. We 

 invariably find that when a group, which Palaeontology 

 or in the absence of direct evidence from fossils, other 

 considerations derived from anatomy or embryology 

 proves to be an ancient group, has a tolerably wide and 

 discontinuous distribution, marked differences in structure 

 distinguish its representatives in different parts of the 

 world. This is more marked still in the case of a group 

 which has but limited powers of dispersal. We shall now 

 illustrate the connection between distribution and ana- 

 tomical structure by a few examples, which are of course 

 few among many ; in other pages other instances have 

 been or will be treated of and reference may be made to 

 those places for further illustration of the general fact. 



Distribution of the Gallinaceous birds. 



The Gallinaceous birds (Alectoromorphse of Huxley) 

 offer an exceedingly instructive example of the connection 

 between anatomical structure and geographical distri- 

 bution. There can be no doubt that this group is a 

 natural one. It is divisible into the following seven 




CH. I] THE GALLINACEOUS BIRDS. 27 



families 1 : Grouse, Turkeys, Guinea-fowls, Pheasants, 

 Megapodes, Curassows and the aberrant Hoatzin (Opis- 

 thocomus). They are thus distributed : 



1. Tetraonidae (Grouse). Palsearctic and Nearctic. 



2. Phasianidae (Pheasants). Oriental. 



3. Numididae (Guinea-fowls). Ethiopian. 



4. Meleagrida? (Turkeys). Southern Nearctic. 



5. Cracidae (Curassows). Neotropical. 



6. Megapodidae (Mound-builders). Australian. 



7. Opisthocomidae (Hoatzin). Neotropical 2 . 



They are not, however, in every case absolutely confined 

 to these regions as defined by Mr Sclater. Thus among 

 the Megapodes one species gets into the Indian region, 

 and the Phasianidae stray into the Palaearctic. The 

 Tetraonidae are really almost cosmopolitan, though mainly 

 massed in the two northern regions of the earth's surface. 

 The Curassows extend into the southern parts of the 

 Nearctic, occurring as they do in Mexico and in California. 

 Such briefly are the facts of the distribution of this group 

 of birds ; it now remains to enquire into the mutual 

 relationships of the several families or subfamilies. Mr 

 Huxley unites the Megapodes with the Cracidae into 

 a group Peristeropodes, and separates them from all the 

 rest which constitute his Alectoropodes. The former 

 division has a sternum with less deeply marked notches, 

 the vomer is well-developed, and the hallux is attached to 

 the foot on a level with the other toes. These characters 

 look as if they were more primitive than the deeply 



1 P.Z.S. 1868. 



- These terms are explained later ; see Chap. II. 




28 STRUCTURE OF GALLINACEOUS BIRDS. [CH. I 



notched sternum, the more rudimentary vomer, and the 

 abnormal position of the hallux in the Alectoropodes. 

 This is very likely so, but as Fiirbringer 1 has pointed out, 

 the structure of the soft parts of the Megapodes are more 

 different from what is found in the Curassows. The latter 

 often have a convoluted windpipe, which does not occur 

 in the Megapodes, but is met with in some Guinea fowls 

 and in the Grouse (Tetrao urogallus). The Megapodes 

 have lost one of the two carotid arteries, and their oil 

 gland has not the tuft of feathers found in other Galli- 

 naceous birds ; in fact, as regards internal structure other 

 than that of the skeleton, the Cracidse are not so very 

 near to the Megapodes. All these structural features 

 will seem perhaps of small moment to the student of 

 invertebrate anatomy ; but it must be remembered that 

 birds form a very circumscribed group ; the anatomist 

 is glad of the smallest characters upon which to found 

 differences ; and the differences enumerated are not small, 

 considering the characteristics of the order. Apart, how- 

 ever, from these differences it does appear the two families 

 Cracidse and Megapodida? are the most primitive Gallin- 

 aceous birds now in existence ; not only do the two 

 points referred to above tend to show this, but we might 

 also perhaps urge the " reptile- like habit " which the 

 Megapodes have of laying their eggs in a heap of dead 

 leaves and abandoning them to the kindness of nature 

 a habit which of course recalls that of nearly all Reptilia. 

 Moreover neither the Curassows nor the Mound-builders 

 show to anything like so great a degree that difference in 

 1 Untersuchungen zur Morphologie der Vopel. 




CH. l] FOSSIL REPRESENTATIVES. 29 



plumage between the sexes which is often developed to so 

 extraordinary an extent in the other members of the 

 group. In many birds which are presumed to be of an 

 ancient type, for instance the Ostrich tribe, there is the 

 same absence of strongly marked secondary sexual 

 characters in colouration. In this particular enquiry we 

 cannot unfortunately get any assistance whatsoever from 

 Paleontology ; the only fossil Megapode recorded in 

 Lydekker's Catalogue of Fossil Birds is Talegalla 

 lathami, a species now living ; there is no information 

 as to extinct Cracidse. The Alectoropodes on the other 

 hand, are much more nearly connected among themselves. 

 Fiirbringer, indeed, does not divide them further 1 . The 

 Guinea-fowls perhaps are the most distinct group ; but 

 the Argus, Pheasant and the Peacock are looked upon 

 by Fiirbringer as somewhat intermediate between them 

 and the more typical Phasianidse. About this group of 

 Gallinacese there is some palaeontological information ; a 

 few existing species (Lagopus albas, Francolinus pictus) 

 have been described from the Pleistocene of Europe 

 and India respectively ; the extinct genus Palceortyx, 

 " Partridge-like birds," containing eight species, occurs in 

 the Eocene and Miocene of Europe ; three species of an 

 allied genus, Palcuoperdix, are also found in the Miocene 

 of Europe; five species of Phasianus have been found in the 

 Pliocene and Miocene of Europe ; four species of Gallus 

 occur in the " superficial deposits " of New Zealand, the 

 " Cavern-deposits of the Lahn valley, Germany " and the 

 Pliocene of France ; of greater interest is the genus Tao- 



1 Nor Gadow with any confidence, see Bronn's " Thierreich." Aves. 




30 CRACID^: AND MEGAPODID^, [CH. I 



perdix (one species only), from the Eocene of France, 

 which is said to present affinities with Numida and 

 Meleagris, i.e. with African and American forms. The 

 facts which have so far been enumerated enable us to 

 draw some interesting conclusions ; the first is indis- 

 putable ; each of the great divisions of the globe is 

 tenanted by a special group of Gallinaceous birds, which 

 is with the exception of the nearly cosmopolite Tetraonidse, 

 confined to that particular region. There are some 

 reasons for considering that the cosmopolitan Tetraonidse 

 are of a less ancient stock than the restricted Cracidas and 

 Megapodidse. There is a closer structural connection 

 between the Gallinaceous birds of the three great con- 

 tinents of Europe, Africa and Asia, than between any one 

 of them and the Gallinaceous inhabitants of South 

 America or remote Australia. The two latter regions, 

 being truly the ends of the earth, are populated by the 

 two most ancient types of Gallinaceous bird, which how- 

 ever are not very closely allied. 



In a very tentative way we may point out another 

 possible conclusion. We may presume that the earth 

 was possessed, as regards Gallinaceous birds, by an ancient 

 stock of which the Cracidse and Megapodidae are the only 

 survivors; later on, from the ancient stock, arose other 

 families which increased and multiplied so much as to 

 drive their forerunners into the more remote corners, 

 where an inroad of the sea preserved them from further 

 competition ; as the remnants of the more ancient 

 race came thus to be widely separated and exposed to 

 divergent conditions they would naturally get to be more 




CH. l] RANGE OF SLOTHS AND ANTEATERS. 31 



and more unlike each other ; hence the differences between 

 the Cracidse and Megapodidse. We find in fact the 

 presumably younger race spreading over the whole earth, 

 while the remnants of the older race are limited to the 

 more remote parts. All this fits in well, as will be 

 remarked later, with the Polar theory of the origin of life. 



Distribution of the Edentata. 



The Edentata are a group of mammals in which 

 the distribution has a very strong relation to anatomical 

 structure. That there is this intimate connection has 

 been shown by recent anatomical investigation, which 

 is summed up and its purport explained in a paper by 

 Sir William Flower 1 , from which the information upon 

 the subject can be most conveniently got. Formerly the 

 members of this group were divided into families not at 

 all consistent with deep lying structure but rather with 

 superficial modification depending upon similar habits 

 and ways of life. Before examining the rational classifi- 

 cation of the group as proposed by Sir William Flower, 

 it will be convenient to briefly pass in review the different 

 genera and families into which the Edentata may be 

 divided. 



The living members of the group readily separate into 

 five families, which are the following : Bradypodidse, or 

 sloths, containing the two genera Bradypus and Cholcepus. 



Myrmecophagidse, or anteaters, with the genera Myr- 

 mecophaga, Tamandua and Cycloturus. 



Dasypodidse, or Armadillos, with the six genera, 



1 P.Z.S. 1882, p. 358. 




32 OLD WORLD EDENTATES. [CH. I 



Tatusia, Dasypus, Xenurus, Priodon, Tolypeutes and 

 Ch lamydopl LOTUS. 



Manidse, or scaly anteaters, with really only one genus 

 Manis, though more have been allowed by some system - 

 atists. 



Orycteropodidse, or Cape anteaters, containing but a 

 single genus Orycteropus. 



Now it has been customary to associate together 

 the anteaters of both the old and the new world, sepa- 

 rating them on the one hand from the sloths and on the 

 other from Orycteropus. We thus get a group ranging 

 over South America, the greater part of the Oriental 

 region, and a large tract of the Ethiopian region, for 

 Manis is found in both of the last named regions. The 

 Manis of the old world has a strong superficial likeness to 

 the anteaters of the new world. The same long tongue 

 and well-developed salivary glands are present in both, 

 while neither of them have any teeth ; correlated with 

 this likeness in structure is the fact that both feed upon 

 ants. The Australian anteater, Echidna, was on this 

 account placed by Linnaeus in the same great group 

 as that containing the Edentata ; it has in the same way 

 a long tongue and well developed salivary glands. There 

 is, however, of course no intimate connection between the 

 animals ; we have here merely a case of modification to 

 the same end, the utilising of an abundant ant or termite 

 supply. The Woodpecker and the Chamseleon show a 

 remarkably analogous modification of the alimentary 

 organs. This is really the only reason, apart perhaps 

 from a general similarity in form, which has led to the 






CH. l] STRUCTURE OF EDENTATES. 33 



uniting of the Old World with the New World anteaters. 

 But an examination of other structures does not show 

 any likeness between the Manis and the Myrmecophaga, 

 but does reveal an unmistakeable resemblance between 

 the latter and the sloth, to which it is so unlike in 

 external form and in habits. In the American anteater 

 the vertebrae to a large extent interlock with each other 

 by an additional series of articular processes, not found 

 in other mammals, excepting only the Dasypodidse, and 

 the extinct Megatheriidse, and which is to a less extent 

 but still obvious in the sloths. This structural resem- 

 blance found in animals of such diverse habit must have a 

 significance in considering their affinities. The fact that 

 the processes in question are in a rudimentary condition 

 in the sloths is correlated with the fact that in those 

 animals which depend from the branches of trees, and use 

 the muscles of the back but little, the articular processes 

 generally of the spine are poorly developed ; the fact is 

 they are of even greater importance as evidence of real 

 blood relationship. As Sir William Flower says, the fact 

 may be almost said to prove " that the sloths are 

 descended from animals in which they existed in a fully 

 developed form." Neither in Manis nor in Orycteropus 

 are there the slightest vestiges of these additional articu- 

 lar processes. It is also pointed out that the shape of the 

 sternum is characteristic of the New World and the Old 

 World Edentates respectively. When we come to other 

 details of structure there is the same alliance to be noted 

 between the various families of Edentata found in America, 

 more particularly is this to be seen in the anatomy of the 



B. z. 3 




EXTINCT EDENTATES. [OH. I 



reproductive organs. On the other hand, the Oryctero- 

 podidaB are not so nearly allied to Manis as are the 

 different genera of New World Edentates among them- 

 selves. But though this is the case it does not show 

 any special affinities with the New World forms. It may 

 be temporarily regarded as a distinct family having 

 (at present) problematic relations to the Manidse, which it 

 resembles by what are principally negative characters. 

 The placenta is an organ which is of great assistance 

 in bringing out affinities between various groups of 

 mammals ; unfortunately it is not known whether the 

 placenta of Orycteropus is deciduate or the reverse ; if 

 non-deciduate there is a likeness to the Manis and not to 

 the New World Edentates. At any rate it is clear that 

 Manis, even if it be not a close ally of Orycteropus, is still 

 further removed from the Myrmecophagidae, Dasypodidae 

 or Bradypodida?. A glance at the structure of the fossil 

 members of the order entirely confirms the broad lines 

 of classification thus laid down by Sir William Flower. 

 The Megatheriidse are in some respects intermediate 

 between the anteaters and the sloths ; the teeth are those 

 of the sloths, but the diminution of their number in 

 the genus Coelodon " leads towards their total suppression 

 in Myrmecopkaga" The lengthening of the skull in 

 Megatherium is another step in the direction of Myrme- 

 cophaga. On the other hand the Old World Edentates of 

 the tertiary period, so far as they are known, lend support 

 to the view that they are more nearly related to the 

 existing Edentates of that part of the world. We have 

 therefore in this group the closest relation between the 




CH. l] DISTRIBUTION OF CUCULID^E. 35 



geographical range of its members and their structure ; 

 there is no confusion possible between the anteaters of 

 the Old World and those of the New, while, unlike though 

 they are outwardly, all the Edentata of the New World 

 form a natural assemblage ; the Edentata of the Old 

 World form perhaps two natural assemblages of equal 

 value to the one of the Old World, but there is no hint of 

 any special resemblance between either and the New 

 World group. 



Though the Gallinaceae and the Edentates thus show 

 a decided relation between distribution and structure, the 

 same is not the case with other plentifully distributed 

 groups of birds. 



Distribution of the Cuckoos. 



The cuckoos will serve as an instance to the point. 

 This family has been investigated anatomically 1 to as 

 great an extent as the Gallinaceous birds ; and the mutual 

 affinities of the numerous genera is to some extent plain. 

 Ftirbringer is of opinion that the genus Phcenicophaes 

 represents more nearly than any other existing form the 

 primitive cuckoo. This is chiefly on account of the fact 

 that it possesses the complete muscle formula, none of the 

 typical muscles of the thigh being absent, and has a 

 syrinx constituted on what must be regarded as the 

 typical plan for birds, viz. the " tracheo-bronchial." The 

 remaining genera have diverged from this in two ways ; 

 either the accessory femoro-caudal muscle has disappeared, 



1 SeeBeddard, P.Z.S.1886. 



32 




36 OLD WORLD AND NEW WORLD CUCKOOS. [CH. I 



or the voice organ has moved down the bronchus pro- 

 ducing that form of syrinx known as the " bronchial." 

 These two changes have in no case occurred simul- 

 taneously. We find either the one or the other. But 

 there is no correspondence between the change in 

 structure and range in space. In both the Old and 

 the New World we meet with cuckoos like Crotophaga 

 and Geococcyx (America) and Centropus (Old World) in 

 which the syrinx is bronchial and the muscles all present. 

 In both hemispheres are cuckoos like our common 

 Cuculus canorus and the American Piaya, in which the 

 trachea has retained the typical form, while the accessory 

 femoro-caudal muscle has completely vanished. If M. 

 Milne-Edwards is right in identifying a fossil cuckoo from 

 the Miocene of France as a Coucal (Centropus) the 

 problem is not rendered any easier. It shows, however, 

 that at this period the two main divisions of the family 

 were differentiated in Europe, whence they may have 

 spread over the world. It must be noted that the genera 

 of the New World are nearly all distinct from those of the 

 Old World, and that it is possible, so far as our present 

 knowledge goes, to distinguish into sub-families by the 

 differences in the arrangement of the feather tracts the 

 New World from the Old World representatives of the 

 two chief subdivisions of the group. This affords an 

 example of a frequently recurring series of facts. It is 

 not of any interest to point out that the American genera 

 are in every case distinct from the African or Indian 

 genera and then to leave the matter. We have to account 

 for, or to attempt to account for, the mutual relationships 




CH. l] FOSSIL CUCKOOS. 37 



between the genera of the different parts of the world. 

 So far as our knowledge of living cuckoos goes the facts 

 have no significance in this connection. Presuming with 

 Wallace that they originated in the tropics of the Old 

 World and thence spread to the New World we have the 

 remarkable fact that in the lengthy journey to South 

 America the two main types already differentiated before 

 migration took place, have been equally successful in 

 colonisation, and have advanced equally far. Fiirbringer 

 holds, and with some justice, that a country inhabited by 

 the oldest form of the group in question is more likely 

 to be its original habitat than elsewhere. In this case 

 Wallace's view that the cuckoos sprang into existence in 

 the Oriental region is supported. But quite recently the 

 whole matter has been put in a rather clearer light. 

 Milne-Edwards has found 1 the remains of a cuckoo which 

 he has relegated to a new genus and which he is unable 

 to distinguish from the living Phcenicophaes. In this case 

 Flirbringer's belief that Phcenicophaes is the nearest 

 approach to the archetypal cuckoo is to some extent 

 justified ; and we have a family formerly of wide range, 

 which is a further proof that it is an ancient form. 

 Moreover if we can now assume that the parent stock 

 of the cuckoos was differentiated in Europe and thence 

 spread over the New as well as the Old World, the 

 difficulties in the way are at least rendered less. 



We shall now indicate briefly the distribution of a few 

 of the principal groups of animals. The mammals and 



1 Comptes Rendus, 1894. 




38 DISTRIBUTION OF TORTOISES. [CH. I 



birds are dealt with later in giving the characters of the 

 different regions and sub-regions. 



Distribution of Chelonia. 



When Mr Wallace wrote his text-book upon Geo- 

 graphical Distribution he was able to make but few 

 remarks upon the distribution of the Chelonia, since the 

 classification was in a very imperfect state, and therefore 

 the bearing of the facts of distribution were not apparent. 

 Now however, thanks to Mr Boulenger's catalogue of the 

 order, we are in a position to deal with the distribution of 

 the group in a manner more satisfactory than was open to 

 Mr Wallace. 



Mr Boulenger divides the Chelonia primarily into two 

 great groups, the Athecae and the Thecophora. The first 

 group is distinguished by the fact that the vertebrae 

 and ribs are free and not connected with the bony 

 exoskeleton. As it only contains a single family, genus, 

 and species, Sphargis coriacea of entirely marine habitat, 

 it need not concern us any further here. The second 

 division of the Chelonia is made up of three super-families, 

 the Cryptodira, the Pleurodira and the Trionychoidea. 

 These together contain eleven families, of which there are 

 seven in the Cryptodira, three in the Pleurodira and only 

 one family in the Trionychoidea. 



Of the first super-family the families Chelydridse (two 

 genera), Dermatemydidaj (three genera), Cinisternidae 

 (one genus) are confined to the American continent. The 

 Platysternidae (one genus) range over S. China, Siam and 

 Burma; there is but a single species which has this wide 




CH. l] DISTRIBUTION OF TORTOISES. 39 



range. The Testudinse is by far the largest family of the 

 Chelonia ; Mr Boulenger divides it into 20 genera, 

 containing between them 113 species which are cos- 

 mopolitan with the exception of Australia and Papuasia. 

 Eleven of these genera are Oriental in distribution. 

 Three are American only. One, Pixys, is confined to 

 Madagascar. Two are confined to Tropical and Southern 

 Africa. Three have a wide range over both the Old and 

 the New World ; among these is the genus Testudo which 

 includes the gigantic tortoises of the Galapagos and the 

 Mascarene islands. The last family is exclusively marine 

 and may therefore be left out of consideration. 



The Pleurodira contains, as already said, three families. 



The Pelomedusa^ have a curious distribution ; its three 

 genera, Sternothwrns, P el o medusa, and Podocnemis being 

 found respectively in Tropical Africa and Madagascar, 

 Africa and Madagascar, South America and Madagascar. 



The family Chelydida3 contains eight genera. Of these 

 five are South American ; two range through Australia and 

 New Guinea, while one, Elsei/a, is only Australian. The 

 family Carettochelydida3 contains but a single genus 

 and species found only in the Fly river in New Guinea. 



The Trionychoidea includes only one family which is 

 made up of six genera. Of these three are East Indian, 

 two tropical African, while the remaining genus Trionyx 

 ranges through Africa, Asia and North America. 



It is obvious from the above summary which I have 

 made complete, owing to the advantage of having 

 Mr Boulenger's list, that South America is the principal 

 home of the land and fresh-water tortoises. The American 




40 DISTRIBUTION OF LACERTILIA. [CH. I 



continent has altogether fourteen peculiar genera. The 

 Oriental region which comes next has fifteen peculiar 

 genera. It may be thought that the Oriental region ought 

 to have been placed first ; but it seems less important than 

 the Neotropical, inasmuch as the latter region has a larger 

 number of peculiar families. The resemblances shown 

 between South America and Madagascar (in the case of the 

 genus Podocnemis) is noteworthy, and has been commented 

 upon elsewhere. The Australian region is poor in tor- 

 toises ; it has only three genera, of which, however, one is 

 the type of a special family, confined to New Guinea. 

 Africa is also poor ; it has but seven peculiar genera, of 

 which several range also into Madagascar, and one is 

 limited to that island. 



The group also shows some remarkable instances of 

 discontinuous distribution. The Chelydidse are limited to 

 the Neotropical and Australian regions ; but, as Mr Blanford 

 points out, this is to be possibly explained by the fact that 

 members of this family are met with in a fossil condition 

 in Europe. It will have been noticed that they are 

 totally absent from New Zealand. 



Distribution of Lizards. 



In this group again the facts have been collected by 

 Mr Boulenger in his British Museum catalogue. The 

 genus Hatteria is excluded from the Lacertilia ; the facts 

 of its distribution have been already considered. The 

 true Lizards contain altogether, according to Mr Boulenger, 

 twenty families. Of these only two approach to being 

 cosmopolite, the Geckotidse and Scincidse ; but the former 




CH. l] THE RANGE OF CHAMELEONS. 41 



appear to be often accidentally conveyed on ships, which 

 at' least shows that they have facilities for becoming 

 cosmopolite ; also they have many archaic points in their 

 structure which point to a long existence in the world. 

 The vertebrae are biconcave and have considerable 

 remains of the notochord between the centra; this is a 

 character which occurs in many ancient forms of vertebrates. 

 Though there are not any other families of Lizards which 

 are so widely spread as those which have been just 

 mentioned there are a few others which have a moderately 

 wide range. This may perhaps be partly attributed to 

 the small size as a rule of the lizards and perhaps to their 

 largely insectivorous habits, which renders them more 

 independent of locality, than if they were vegetarian. 

 The fact that many occur upon oceanic islands is a fact 

 which shows that they have greater powers of dispersal 

 than many other groups of animals, and at the same time 

 necessarily renders the study of their distribution less 

 interesting. 



The families Eublepharidse, Iguanidae, Anguidse, Am- 

 phisbaenidae, and Anelytropida? are found in both the Old 

 and the New Worlds. The bulk of the Iguanidae are, 

 however, tropical American, and are very characteristic of 

 the region. The Chameleons have a distribution which is 

 remarkably parallel, as M. Trouessart has pointed out, to 

 that of the Lemurs. The bulk of them are found in 

 Madagascar only, but they also range into Africa and the 

 East Indies. Their arboreal habits, as also in the case of 

 the Lemurs, is perhaps to be compared with their 

 comparatively limited range. A very characteristic Old 




42 MONITORS. [CH. I 



World family is that of the Monitors (Varanidae) ; there 

 are a large number of species which range over the 

 Oriental, Ethiopian and Australian regions ; the group 

 comprises some of the largest of lizards, arid some of them, 

 such as the Nilotic Monitor which lives upon the eggs and 

 young of the Crocodile, are aquatic in their mode of life. 

 The structure of the Monitors is such as to separate them 

 very widely from other lizards ; but they have no 

 particular relationship, as was at one time held, to the 

 peculiar American family of the Teiid;e, of which the 

 Teguexin is an example. The Lacertidaa are also a 

 peculiarly Old World family. To them belong two out of 

 the four indigenous lizards of this country. The fourth, 

 the Blind worm, is the representative of the family 

 Anguidae. The most limited range of any family is 

 afforded by the Helodermatidae, containing but one genus, 

 Heloderma, the Gila monster of the state of Arizona. 

 With one possible exception, it is the only poisonous 

 lizard. Australia has one peculiar family of lizards, the 

 Pygopodidae. America has two others besides those 

 mentioned, viz., Xenosauridae and Xanthusiidse. The 

 distribution of the lizards undoubtedly shows a marked 

 difference between the Old and New Worlds. Moreover the 

 Old World is more logically to be divided perpendicularly 

 than horizontally according to Dr Giinther. He would 

 divide the world into six regions, (1) America, (2) Africa 

 and Europe, (3) India and the Mantchurian sub-region of 

 the Pala^arctic, (4) Madagascar, (5) Tropical Pacific, and 

 (6) New Zealand, characterised of course as far as the 

 true lizards are concerned by negative characters. It is 




CH. I] AFFINITY BETWEEN AFRICA AND EUROPE. 43 



interesting to notice that the lacertilian fauna of Africa 

 attaches itself to that of the western Palsearctic region ; it 

 has often been remarked that Europe is really African in 

 its affinities ; this however has been to a large extent 

 disguised by the destruction of animal life or its removal 

 due to the glacial period. It will be remembered that 

 before the glacial period and during the interglacial 

 periods (?) there were Hippopotami, Hyenas &c. in 

 Europe. Mr Boulenger unites Australia with the Oriental 

 region, an union which is confirmed by the consideration 

 of other groups of animals of some age, e.g. earthworms 

 and crocodiles, and is accepted by botanists. 



The Distribution of Crocodiles. 



The distribution of the Crocodilia is very interesting, 

 and on the whole fits in with the known laws of the 

 distribution of animals. Fortunately one of our foremost 

 authorities on the system of reptiles, Mr Boulenger, has 

 recently summed up the existing knowledge of the range 

 of the group in the British Museum Catalogue. He 

 allows seven genera, Gavialis, Tomistoma, Crocodilus, 

 Ostolcemus, Alligator, Caiman and Perosuckus. There are 

 eleven species of Crocodilus, three of Alligator, and five 

 of Caiman ; the remaining genera consist of a single 

 species apiece. As might be supposed from the large 

 number of species into which it is divisible, the genus 

 Crocodilus has the widest range of all the Crocodiles. It 

 occurs in all the tropical regions of both the Old and the 

 New World. Alligator was believed until recently to be 

 confined to America; but the existence of a Chinese 




44 DISTRIBUTION OF CROCODILES. [CH. I 



species, A. sinensis, was made known in 1879. The 

 Caimans and Perosuchus are exclusively tropical American. 

 Ostolcemus is West African. Gavialis is confined to some 

 of the rivers of India, while Tomistoma has only been met 

 with in Borneo. 



Though the two latter genera by their elongated 

 snouts suggest the Mesozoic Teleosaurians, it seems 

 probable that Caiman and Perosuchus represent the 

 most archaic among the existing Crocodilia. The reason 

 for this opinion is that they alone possess a ventral as well 

 as a dorsal armature of scutes, such as were developed in 

 forms like the Wealden Bernissartia, in which the ancestor 

 of both Crocodiles and Alligators is seen by some. To a 

 feeble extent the ventral scutes are to be found in 

 Alligator, and also apparently in Ostolcemus. This, it 

 will be noticed, is quite in accord with the wide but 

 discontinuous distribution of those genera, which might 

 almost on this account be put into a separate family. The 

 presumption would be that formerly they were more 

 widely spread, but that the process of time produced gaps 

 in their ranks, leaving the present detached fragments. 

 The existence therefore of an Alligator in China is not so 

 remarkable if this point of view be borne in mind. 



As to the true Crocodiles of the genus Crocodilus, they 

 are characterised also by the fact that there are constantly 

 fifteen teeth only in the lower jaw ; the old idea that a 

 Crocodile could always be distinguished from an Alligator 

 by the fact that the fourth tooth in the lower jaw was 

 received into a notch instead of into a pit in the upper 

 jaw has been exploded by the discovery that in an 




CH. l] CROCODILES OF OLD WORLD. 45 



undoubted Crocodile, C. palustris, both conditions may 

 occur. The reduced number of teeth is another indication 

 of the more modern character of the genus Crocodilus. 

 The wide distribution of the genus is indicative of a 

 younger and more vigorous stock, as is also perhaps the 

 larger size of many Crocodiles as compared with Alligators. 

 In Mr Boulenger's catalogue the measurement of no 

 Alligator is stated to exceed 4 metres, and they are 

 generally much smaller than this ; on the other hand the 

 Crocodile of Madagascar is said to reach a length of 

 thirty feet, and generally the Crocodiles are large. If 

 this view respecting the geographical and structural 

 relations to the Crocodilia be the correct one it is 

 significant that in this case as in so many others the 

 archaic forms have chiefly gravitated towards South 

 America. 



The bearing of the facts in the distribution of this 

 order upon the generally recognised zoo-geographical 

 regions seems to comply with a primary division of the 

 earth's surface into Palaeogsea and Neogaea; there is 

 apparently less difference between the Oriental and 

 Australian regions than between either of them and the 

 Ethiopian, though the difference here is but slight. 

 The fact that Crocodiles can traverse the sea is 

 perhaps partly responsible for the absence of peculiar 

 types in the Australian continent, which is connected 

 with Asia by so many intervening islands. It is also 

 perhaps a testimony to the age of the group as contrasted 

 for example with the more modern mammals and birds. 




46 RANGE OF COLUBRINE SNAKES. [CH. I 



The Distribution of Snakes. 



The following account of the range of this order will 

 be limited to the Colubrine section, since Mr Boulenger's 

 catalogue, whence my information is derived, has not yet 

 reached the Vipers. The Colubrines, which are chiefly 

 though not entirely non-venomous serpents, may be divided 

 into seven families, the Typhlopidse, Glauconiidse, Boidse, 

 Ilysiidse, Uropeltidse, Xenopeltidse and Colubridse. Two 

 of these families, the Uropeltidse and Xenopeltidse, are 

 entirely confined to the Old World ; the former family 

 contains only seven genera of burrowing snakes which are 

 limited in range to Ceylon and other regions of India. 

 The Xenopeltida3 is a still smaller family, for it contains 

 only a single genus and species, which occurs in S. E. Asia. 

 The other families are more or less cosmopolitan. The 

 two largest of these are the Boidse and the Colubridae. 

 The Boidse are again subdivisible into two groups, the 

 true Boas and the Pythons. The latter are nearly entirely 

 Old World in habitat, the only exception being the Mexican 

 Loxocenius. On the other hand the Boinse are nearly as 

 exclusively American ; out of the thirteen genera which 

 Mr Boulenger allows in the sub-family six are purely 

 American, one belongs to the Australian region, one is 

 common to Asia and Africa, and two genera, Casarca and 

 Bolieria, consisting of a single species apiece are restricted 

 to Round Island near to Mauritius ; there remain the two 

 genera Corallus and Boa ; these are remarkable for the 

 fact that while both are almost entirely American or 

 Antillean in range they contain one or two species which 




CH. I] FROGS AND TOADS. 47 



are found in Madagascar, a state of affairs which is paral- 

 leled in some other groups. 



On the whole the snakes emphasise the necessity of 

 drawing a sharp line between the Old and New World, as 

 indeed do all the reptiles. 



Distribution of Batrachia. 



While the Urodele Amphibia are limited to the 

 northern hemisphere, the frogs and toads have a nearly 

 world-wide range ; the only places where they are uniformly 

 rare are true oceanic islands ; as will be explained, facilities 

 for crossing the sea are entirely wanting. The occurrence 

 therefore of a true frog in the Solomon islands is one of 

 the chief proofs, from the zoological side, that this island 

 is not a real oceanic island ; a species which occurs in that 

 island (there are eight others) is the largest of all existing 

 frogs and toads and is known as Rana guppyi. The Fiji 

 islands possess three species of the genus of frogs Comufer. 

 This family, the Ranidae, is nearly cosmopolitan ; but the 

 toads comprised in the family Bufonidse are more nearly 

 completely cosmopolitan. The tree frogs, Hylidse, are also 

 very widely distributed ; but as is natural they find their 

 greatest development in " Dendrogaea," the Neotropical 

 region. Oddly enough these often purely arboreal crea- 

 tures, some of which do not even lay their eggs in pools, 

 are totally absent from the forests of Africa, indeed from 

 the Ethiopian region altogether. The lowly organised 

 group of frogs, Aglossa, comprise two families, the Pipida3 

 and the DactylethridaB ; the latter are in more than one 

 particular near to the tailed Amphibians ; they are, for 




48 FAMILIES OF BATRACHIA. [CH. I 



instance, more thoroughly aquatic than the Ranidae ; they 

 sprawl about awkwardly on land instead of sitting up in 

 the alert though broken-backed fashion of other frogs ; 

 the eggs too are laid not in masses as are those of the 

 common frog, but singly as in the newt. This family is 

 restricted to tropical and southern Africa ; the Pipidse 

 including only the genus Pipa, in which the female 

 harbours the young in holes in the skin, is Brazilian. 

 Two families, Amphignathodontidse and Hemiphractidse 

 are peculiar to the Neotropical region. The family of the 

 Cystignathidae are remarkable in being found in the 

 Neotropical and Australian regions ; the family contains a 

 large number of species of which several have the habits 

 of the tree frogs ; and one genus has been on this account 

 termed Hylodes. A very characteristic member of this 

 family is the "Barking toad" of South America, Ceratopkrys 

 ornatus, of which specimens may be always seen at the 

 Zoological Society's gardens. Another instance of discon- 

 tinuous distribution is offered by the family Discoglossidae, 

 which occurs in all the sub-regions of the Palsearctic 

 region and has a single representative in New Zealand, 

 viz. Liopelma hochstetteri. Resemblances between South 

 America and Madagascar are shown here, as in some other 

 groups of the animal kingdom. The family Dendrobatidae 

 are represented by two genera Mantella and Stumpffia, 

 comprising five species, in Madagascar, and by the genus 

 Dendrobates in South America. On the whole the Neo- 

 tropical region is most abundantly inhabited by peculiar 

 forms. Out of the fourteen families allowed by Mr 

 Boulenger no less than ten are found in that realm and 




CH. l] BATRACHIA OF MADAGASCAR. 49 



as already mentioned four are absolutely confined to it. 

 No other region has more than seven of the families 

 found in it. And the Ethiopian is the only other region 

 which has a family all to itself, viz. the Dactylethridse. 

 The Ethiopian and the Oriental regions are allied by 

 their Batrachian fauna. Madagascar for example shares 

 with the Oriental region nearly all its genera ; the Ranid 

 genus Rhacophorus is characteristic of the east, where it is 

 represented among other species by the flying frog, R. 

 reinwardti, the size of whose hind limbs and the amount 

 of webbing between them is said to have increased 

 progressively in illustrations of the animal. The family 

 Discophidse is limited to these two regions; indeed but 

 for a single Burmese species it is purely Mascarene. 



The Distribution of Scorpions. 



It is greatly to be wished that other specialists would 

 do as Mr Pocock has done and put together a brief account 

 of what is known respecting the geographical range of 

 their groups. In a recent number of Natural Science 1 

 we have an epitome of the distribution of scorpions. 

 The existing genera, 60 in number, are divided among 

 eight families. All of these are tropical or sub-tropical in 

 range. No scorpions are found in the more northern 

 latitudes and they are entirely absent from New Zealand. 

 On the other hand they occur in Patagonia. In Europe 

 the northernmost limit is the south of France and the 

 shores of the Mediterranean generally. In Asia lat. 40 C 



i May, 1894. 

 B. Z. 4 




50 DISTRIBUTION OF SCORPIONS. [CH. I 



marks their northern limit. In America they do not, 

 according to Mr Pocock, get quite so far north as this. 

 Although the scorpions are an extremely ancient race, 

 beginning in the Silurian, and occurring there and in the 

 Carboniferous in the shape of forms which hardly differ 

 from existing species, the modern representatives show a 

 range which corresponds with that of existing continents. 

 The existing scorpions are nearer to the carboniferous 

 Anthracoscorpii in that the feet terminate in two claws 

 instead of in the single claw of the Silurian Palceopkonus, 

 which Thorell has relegated to another group, the Apoxy- 

 podes, reserving the name Dionychopodes for the others. 

 Mr Pocock deduces from a comparison of the slight differ- 

 ences in structure between the ancient and the modern 

 forms certain facts of structure which may be looked upon 

 as archaic ; though these seem to those accustomed to the 

 structure of other groups very minute it is evident that 

 we must be content with them owing to the already 

 mentioned homogeneity of the group. In the most ancient 

 scorpions the lateral eyes are behind the median eyes, 

 which are placed at the front edge of the thorax. We 

 should regard therefore those scorpions in which the eyes 

 approximated most to this primitive position as the oldest. 

 Another point is the pentagonal sternum which though 

 lost in many adults reappears invariably in the young. 

 Finally the existing Buthidse contain genera in which 

 there is a spur upon the fifth joint of the last two pairs of 

 limbs, a structural feature which gets its importance from 

 the fact that it has also been described in the Silurian 

 Palceophonus. Indeed it is the Buthidse which show to a 




CH. l] SCORPIONS OF AFRICA. 51 



greater extent than any other family all these three 

 archaic characters. And in correspondence with this we 

 find them ranging widely with many peculiar genera in 

 different parts of the world. The different regions differ 

 considerably in the richness of their scorpion fauna. 

 Naturally considering the tropical proclivities of the 

 family the Palsearctic region shows the fewest peculiar 

 generic types ; Mr Pocock only enumerates eight ; but 

 some of these range further into Africa than it is customary 

 to allow the Palsearctic region to extend, the northern 

 limit of which is placed considerably below the tropic of 

 Capricorn. Africa is very rich in scorpions ; unfortunately 

 those of Madagascar are but little known ; what is known 

 however tends to emphasise the peculiarities of this great 

 island ; two peculiar genera Grosphus and Tityobuthus, 

 belonging to the Buthidse, are there to be found. In the 

 Ethiopian region, apart from Madagascar, there exist no 

 less than nine peculiar genera exclusive of the two just 

 mentioned besides four that get into other regions. The 

 Oriental region is on the whole very distinct from the 

 Ethiopian though naturally they have some forms in 

 common. Six genera are confined to the region. Of the 

 five that are not, three are also partly Ethiopian ; two of 

 those are also Australian, viz. Isometrus and Archisome- 

 trus\ while Hormurus just gets across "Wallace's line." 

 In the Australian region there are altogether seven genera, 

 of which only three are peculiar and all of these three are 

 limited to what Mr Pocock calls the Australian sub-region, 

 i.e. the continent of Australia. The range of the scorpions 

 in fact rather supports what I have said concerning the 



42 




52 SCORPIONS OF AMERICA. [CH. I 



range of earthworms that the Australian region should 

 be limited to the continent of Australia itself. It has 

 been mentioned that several of the genera of Old World 

 scorpions range into as many as three regions. We find 

 however no community at all between the scorpions of the 

 Old World and those of the New, excepting in the single 

 case of Cercophonius which has an Australian representa- 

 tive. There is too a considerable difference between the 

 Nearctic and the Neotropical. Only two genera are common 

 to the two, viz. Centrums and Diplocentrus. The Nearctic 

 which is only that portion of the Nearctic termed 

 Sonoran by Hart Merriam is inhabited by three other 

 genera. On the contrary the Neotropical region is ex- 

 ceedingly rich in scorpions. Mr Pocock mentions twenty- 

 two genera. As to families there is one, that of the 

 ChactidaB, which is absolutely confined to the Neotropical 

 region. 



To express the distribution of the scorpions in accord- 

 ance with the facts it would therefore be necessary first of 

 all to separate the Old from the New World and then to 

 divide them into regions which apart from details resemble 

 those of Mr Sclater. The distribution of these animals 

 lends no assistance whatever to some of the suggested 

 continents that have been referred to. There is no re- 

 semblance between those of South America and South 

 Australia. And as already mentioned there are no 

 scorpions at all in New Zealand. But it must be borne 

 in mind that at present there is no information concerning 

 the scorpions of Patagonia, whence information of an 

 important character may come. There is however a close 




CH. I] LAND PLANARIANS. 53 



resemblance between the South African genus Opisthocen- 

 trus and the Panaman Opisthacantkus, and between the 

 only two genera of the Diplocentridae, Diplocentrus and 

 the Arabian Nebo. This may be merely a relic of former 

 warm periods prevailing in the north, of which the 

 existence of Tityus in amber of the Baltic is a further 

 indication. This genus now occurs south of the tropic of 

 Capricorn, thus indicating a state of climate favourable to 

 the migrations of scorpions by Behring's Straits. 



The Distribution of Land Planarians. 



This group of worms is one that should be of great 

 use to the student of geographical distribution. The land 

 Planarians are of course of an ancient stock though 

 the modern representatives may be recently derived from 

 some one branch of this stock. They are purely terres- 

 trial animals, always an advantage in considering the 

 problems of Zoogeography ; and finally it is probable, 

 though it is uncertain whether there are any actual 

 facts that can be alleged in support of the contention, 

 that the animals, having a coating of cilia and secreting 

 from their skin a slimy mucus, would be destroyed by 

 contact with salt water. It is however only recently that 

 attention has been actively directed towards the study of 

 this group of the Planarian worms. The late Prof. 

 Moseley took advantage of the opportunities afforded him 

 during the cruise of the " Challenger " to collect and 

 describe a considerable number of new forms ; the litera- 

 ture which he gives of the subject in his paper 1 shows 



1 Quart. Journ. 3Iicr. Set. Vol. xvu. 




54 RANGE OF B1PALIUM KEWENSE. [CH. I 



how little had been done in the matter before his time. 

 Nevertheless what was accomplished by him and by Dendy, 

 Spencer, von Graff and the others who have succeeded 

 him has brought to light a good deal; we are in a position 

 to say something about the range of the group. The land 

 Planarians are as is known an artificial group ; they em- 

 brace the terrestrial forms among the Triclad Turbellaria. 

 The most familiar form in the whole group is the cele- 

 brated Bipalium kewense, which is an absolute cosmopolite; 

 it has been found in many localities in England such as 

 Kew whence it was first obtained, the Zoological Gardens, 

 &c. It has turned up on the continent, in Brazil, Australia 

 and elsewhere ; but its real home appears to be the 

 Fijis. With this exception, which is probably due to 

 artificial importation, there is no species of land Planarian 

 which is so widely spread, indeed no species has a great 

 range at all even in the country which it inhabits. Mr 

 Dendy has 1 pointed out from his study of the Australian 

 species that "out of twenty-nine known Australian species, 

 nearly equally divided between the colonies of Victoria 

 and New South Wales, only three have been found in both 

 colonies"; he goes on to remark with justice "that the 

 land Planarians however widely they may be distributed 

 as a class do not enjoy wide specific area of distribution. " 

 This fact of itself makes them exceedingly valuable as 

 examples of the importance of an invertebrate group in 

 contributing towards the solution of the problems of Zoo- 

 geography. So far as we know at present there are three 



1 Trans. Roy. Soc. Viet. 1890, p. 66. 




CH. l] LAND PLAXARIAXS OF THE EAST. 55 



main groups of these worms ; the Rhynchodemidae, with 

 two eyes, the Geoplanidas with many eyes and the 

 Bipaliidse with four eyes and a hammer-shaped head. 

 Bipalium, with the exception of the probably accidentally 

 imported B. keweme, already referred to, is confined to 

 China, Borneo, Bengal, Ceylon and the Oriental region 

 generally. Geoplana is Australian, S. African, Japanese, 

 New Zealand, South American; and recently two species 

 have been described among the rich material collected by 

 Dr Max Weber in the Dutch East Indies. Curiously 



V 



enough that naturalist, so Dr Loman 1 tells us, was quite 

 unable to discover any land Planarians of any kind in the 

 island of Celebes, although he searched for them with 

 great care. Cotyloplana, also belonging to the same divi- 

 sion of the genus, is confined to Lord Howe Island, whence 

 it was brought by Prof. Spencer. The genus Coeloplana 

 of Moseley is included by recent writers in Geoplana. A 

 species of Geoplana was described by the late Dr Gulliver 

 from the island of Rodriguez. In all probability this 

 genus of such wide range will bear splitting up. But in 

 the meantime Prof, von Graff notes that it is mainly 

 developed in South America. Not less than 68 of the 125 

 species known to Dr v. Graff are inhabitants of the conti- 

 nent of South America. Rhynchodenms has also a wide 

 range. It is met with in Europe, at the Cape of Good 

 Hope, in Australia, in North and South America, Ceylon, 

 Samoa, and the Dutch East Indies. Other genera are the 

 European Geodesmus, Microplana described by Vejdovsky 

 from dung hills, Geobia subterranea of Brazil which as its 



1 Zoolog. Ergebn. Max Webers Reise. 




56 LAND PLANARIANS : AN ANCIENT GROUP. [CH. I 



name denotes lives under ground and subsists upon earth- 

 worms as do indeed many of the species, which are for 

 the most part carnivorous. A species in Europe which 

 nourishes itself upon fungi has however been recorded. 

 The two genera Leimacopsis and Polycladus are recorded 

 from the Andes *, and the former at any rate is the type 

 of a group distinct from any of those that have been 

 mentioned. Moseley described from the Philippines the 

 peculiar genus Dolichoplana. Now it will be observed 

 that the bulk of the species belonging to the Geoplanidae 

 are South American and Australian. Only a few range 

 to the north of those land masses. This may be a fact of 

 some importance. The reader will have already made 

 himself acquainted with the division of the earth proposed 

 by Mr Huxley. The Geoplanidse are almost exclusively 

 restricted to his Notogaea; and this restriction agrees 

 with that of certain other ancient forms of terrestrial 

 animals such as the Marsupials. The distinctness of the 

 Oriental region as shown by the land Planarians is also 

 remarkable. It would not of course be remarkable if we 

 were dealing with a modern group ; but the wide range of 

 Geoplana is so far an argument that we are dealing with a 

 fairly ancient group. 



Altogether it seems to be evident that when the land 

 Planarians come to be more extensively known they will 

 yield a highly valuable body of facts ; in the meantime 

 this slight sketch of their distribution may serve to il- 

 lustrate the impossibility of laying down hard and fast 

 regional districts to apply to every group. 



1 Schmarda, Neue wirbellose Thiere, 1861. 




CH. l] EARTHWORMS OF SEA SHORE. 57 



The Distribution of Earthworms. 



The geographical distribution of the earthworms offers 

 an instance of a group that is now fairly well known and 

 is at the same time in all probability a moderately ancient 

 group. It has too exceptional qualifications for careful 

 consideration in relation to the theories of past changes of 

 land in connection with the range of existing forms. 

 As a rule earthworms are killed by salt water; there 

 are exceptions such as the genus Pontodrilus which 

 actually lives upon the sea shore within range of at least 

 the splashing of the waves, and it has been asserted that 

 a few species in Ceylon (not named) can withstand the 

 action of sea water. But with these exceptions the ocean, 

 even when in the form of a narrow strait, is an insuperable 

 barrier, which is more effective than any other. As worms 

 have been met with at great heights upon the mountains, 

 there seems to be no particular difficulty in their extend- 

 ing their range by crossing mountain chains ; probably 

 also rivers and large lakes are not untraversable ; experi- 

 ments show that earthworms can be kept for some days 

 immersed in fresh water and yet retain their vitality, while 

 there are a good many instances not only of true earth- 

 worms (in structure) which habitually live in the water, 

 but there are species which live with equal ease in water 

 and on dry land. This is true of the European Allurus 

 tetrcedrus and of several species of Acanthodrilus. An 

 arid desert would doubtless prove as effectual a barrier to 

 migration as the sea. The only defect in this group with 




58 FAMILIES OF EARTHWORMS. [CH. I 



regard to the problems afforded by geographical distribu- 

 tion is the entire absence of any knowledge whatsoever 

 about extinct forms. We cannot therefore compare the 

 past with the present. 



Earthworms are divisible into seven families : Crypto- 

 drilida?, Pericha3tidae, Acanthodrilidae, Eudrilidge, Geo- 

 scolicidse, Moniligastridae, and Lumbricidse. Of these the 

 first three are very nearly related and may be united into 

 one super-family Megascolicida^, which possibly is really 

 equivalent to any of the other families Eudrilidae &c. 



The Cryptodrilidse are world-wide, but most abundant 

 in the Australian region and in South America. The 

 Pericha?tida3 are chiefly Australian and Oriental, but 

 occur in the Neotropical and Ethiopian regions. The 

 Acanthodrilidas are mainly massed in New Zealand, 

 South America, and Africa ; they are also found, though 

 rarely, in Australia, Malaya and North America. The 

 Eudrilidae are absolutely confined to Tropical Africa, 

 the Geoscolicidjje to Tropical South America, Tropical and 

 Southern Africa, just reaching Europe and Malaya. The 

 Lurnbricidse are probably only indigenous in the Nearctic 

 and Palaaarctic regions. 



But it is necessary to go into further details to bring 

 out the salient facts in the distribution of the Oligocha3ta. 



The list, which I shall now give, is freed from obvious 

 importations like the Lumbricidse of exotic range dealt 

 with elsewhere. The same kind of argument removes 

 the Perichaetida3 from the Nearctic and Palsearctic 

 regions. Two genera belonging respectively to the Geo- 

 scolicidse and Eudrilidse, viz. Pontoscolex and Eudrilus are 




CH. I] DISTRIBUTION OF GENERA. 59 



of world- wide range ; but it is to be noted that the same 

 species exists everywhere, and that they are among the 

 most abundant of species in accidental or purposeful 

 importations of worms, thus arguing not only great 

 probability of their accidental introduction but showing 

 clearly that they can easily survive a long journey. This 

 is as far as I think it safe to go at present, but Michaelsen 

 goes further and would confine the genus Perichceta to 

 the Old World and the genus Benhamia to the Ethiopian 

 region. The genera of earthworms are thus distri- 

 buted :- 

 Palsearctic. Lumbricus,Allolobophora, Allurus (L) 1 , Ponto- 



drilus, Microscolex (C), Hormogaster (G). 

 Nearctic. Lumbricus, Allolobophora, Allurus (L), Mega- 



scolides, Ocnerodrilus, Microscolex (C), Diplocardia, 



Benhamia (A). 

 Oriental. Perichceta, Megascolex, Pleionog aster, Perionyx 



(P), Benhamia (A), Glyphidrilus, Annadrilus (G), 



Typhceus, Deodrilus (C), Moniligaster, Desmogaster 



(M). 

 Ethiopian. All Eudrilidse, Microchceta, Kynotus, Siphono- 



gaster, Ilyodrilus, Bilimba, Callidrilus (G), Benhamia, 



Acanthodrilus (A), Megascolex, Perionyx (P), Mill- 



sonia, Ocnerodrilus, Gordiodrilus (C). 

 Neotropical. Rhinodrilus, Anteus, Geoscolex, Tykonus, 



Urobenus, Pontoscolex, Onychochceta, Diachatta, Tricho- 



chceta (G), Microscolex, Ocnerodrilus, Gordiodrilus (C), 



Acanthodrilus, Kerria (A), Perichceta (P), Monili- 



gaster (M). 



1 The capital letters in brackets indicate the family. 




60 ANTARCTIC EARTHWORMS. [CH. I 



Australian. Perichceta, Megascolex (P), Cryptodrilus, 

 Megascolides y Dichogaster, Microscolex (C), Acantho- 

 drilus, Octochcetus, Deinodrilus (A). 

 The above list shows how well marked the regions 

 are ; but it loses half its significance without further 

 explanation. New Zealand is really very different from 

 Australia ; it has practically only Acanthodrilidse ; con- 

 fined to it are the genera Octochcetus, Plagiochceta and 

 Deinodrilus,&nd out of the eleven species of Acanthodrilus 

 found in the region eight are New Zealand and only three 

 Australian ; Microscolex only just gets into Australia, 

 which is characterised by its PerichastidaB (feebly repre- 

 sented in New Zealand), and by the genera Cryptodrilus 

 and Megascolides. The Neotropical region is really 

 divisible into two ; the southern half including the greater 

 part of the Argentine and Chili has only Acanthodrilus 

 and Microscolex, while the Geoscolicidse are confined 

 to the tropical regions. There is thus the closest 

 resemblance between South America and New Zealand 

 which is accentuated by the fact that in intervening 

 localities South Georgia, the Falklands, Marion and 

 Kerguelen islands only Acanthodrilus exists. These 

 evidences in favour of an antarctic continent are referred 

 to again later. The tropical regions of Africa and America 

 agree in the presence of the Geoscolicidae which only just 

 reach Europe and the Oriental region ; moreover the 

 African genera fall into a natural sub-family distinct from 

 that which contains the American forms. This fact again 

 has its counterpart in the Edentata among Mammals and 

 in some other groups. 




CH. l] RANGE OF PERICH^TID^. 61 



The family Perichsetidse shows some remarkable 

 distributional facts. It may be divided perhaps into 

 five genera all of which have the complete or nearly 

 complete circle of setae which characterise the family ; 

 but they differ in other particulars. Megascolex and 

 PerichcBta have the nephridial system arranged in what 

 I have termed the diffuse fashion ; they are in Mr 

 Benham's terminology " plectonephric." In them there 

 is not a definite series of paired nephridia, but an 

 infinity of minute tubes which open on to the exterior by 

 innumerable pores in each segment. On the other hand 

 Diporochceta and Perionyx have the normal paired 

 nephridia. The genus Perichcuta is also to be dis- 

 tinguished by the fact that very nearly all the species of 

 the genus have a pair of cseca arising from the intestine 

 at about the twenty-fifth segment. Now in Australia the 

 prevailing forms are Megascolex and Diporochceta. Peri- 

 chceta does occur, but there are not more than two or 

 three species. Diporochceta just gets into New Zealand. 

 As we pass from Australia into the Oriental region the 

 genus Megascolex is replaced by Perichceta which is the 

 prevalent type not only of the family but of earthworms 

 in general in the islands of the Malay Archipelago and 

 the continent of India. Megascolex however lingers on, 

 just fading away in Madagascar. The Oriental region is 

 further characterised by another genus Perionyx which 

 agrees with Diporochceta in the regularly paired nephridia 

 but differs in the fact that the glands into which the 

 sperm ducts open before reaching the exterior have a 

 coarsely lobate arrangement instead of being coiled tubes 




62 RANGE OF PERICH^TID^E. [CH. I 



of equal calibre throughout. This genus just gets into 

 the Ethiopian region where it is represented by the 

 species Perionyx zanzibaricus, and possibly by another at 

 Durban. The true Perichceta is rare in Africa but 

 reappears on the opposite side of the Atlantic in Tropical 

 America and the West Indies. As there are a con- 

 siderable number of species on one side of the Atlantic 

 which are not found upon the other it seems likely that 

 the genus is indigenous in the New as in the Old 

 World. 



It is held by some that the characteristic mark of the 

 PerichaBtidaa. the continuous circle of setaB amounting 



o 



often to more than one hundred in a single segment, is a 

 primitive arrangement from which the more general eight 

 setae per segment can be derived by reduction ; at present 

 however the matter is one which cannot be definitelv 



V 



decided. If it prove ultimately to be the correct view, it 

 is noteworthy that the genus, like other ancient forms, 

 has a wide and discontinuous distribution, starting in the 

 Old World, and skipping Africa and Europe almost 

 entirely to reappear in the more tropical parts of America. 

 Moreover it is significant that in this group, as with the 

 mammals, Australia has the more ancient forms. 



The family GeoscolicidaB present some interesting 

 facts in their distribution. The family is one of the more 

 modern, on the view that I take myself of the affinities of 

 the group. The spermathecse have lost or at any rate do 

 not possess the diverticula so characteristic practically 

 universal in the Megascolicida?. In this they agree 

 with the European Lumbricidse our common earthworms 




CH. I] RANGE OF GEOSCOLICID.E. 63 



in this country in which the spermathecse are oval or 

 roundish pouches without any caeca attached to them. 

 But the Geoscolicidse agree with the majority of earth- 

 worms to differ from the Lumbricidse in that the gizzard 

 is as it were strung upon the oesophagus, instead of lying, 

 as it does in Lumbricus, at the junction of oesophagus and 

 intestine. The nephridia are always paired ; but the 

 setse differ from those of the Lumbricida? in being nearly 

 always ornamented with raised ridges or sculpturing of 

 some sort ; moreover there is frequently a difference 

 between those which occur on the segments of the 

 clitellum and those which are found elsewhere upon the 

 body. The Geoscolicidse of Africa belong to the genera 

 Microchceta, Siphonog aster, Ilyogenia and Callidrilus. I 

 have already referred to Kynotus of Madagascar which 

 is allied to these but still is different from any of them. 

 The family extends in the Old World into the Malay 

 region where it is represented by the two allied forms, 

 perhaps hardly generically separable, Glyphidrilus and 

 Annadrilus. It is represented in Europe by Hormogaster, 

 whose affinities are uncertain. Putting aside Siphono- 

 gaster, which is a remarkable and isolated type with two 

 extraordinary processes of the ventral body wall which may 

 be of the nature of penes, and Ilyogenia which may be, as 

 has been suggested by Dr Michaelsen, really a repre- 

 sentative of another family which has got to resemble the 

 GeoscolicidaB by convergence, all these Ethiopian and 

 Oriental genera are alike in having a great number of 

 small spermathecae in several segments of the body and in 

 having for the most part a glandule-muscular structure at 




64 EARTHWORMS OF WEST INDIES. [CH. I 



the outlet of the sperm ducts and often a series of glands 

 which have been called for want of a better name " copu- 

 latory " glands which show a structure identical with that 

 of the glands at the end of the male ducts. In tropical 

 South America and in the West Indies are the following 

 genera belonging to this family : Geoscolex, Anteus, 

 Rhinodrilus, Urobenus, Pontoscolex, OnychocJueta, Tricho- 

 chceta, Diachceta, Tykonus. These genera, if they possess 

 spermathecaB, which they do as a rule, have them paired as 

 in the majority of earthworms. A representative of this 

 group Sparganophilus has been lately discovered by Dr 

 Benham in the Thames, and Criodrilus, usually referred 

 to the LumbricidfB, perhaps belongs to the group, though 

 its position cannot be at present regarded as certain. It 

 is likewise European. It is a remarkable fact that 

 the West Indian genera present considerable differences 

 from the genera found on the mainland of South 

 America. All of them, viz. Pontoscolex, Onychochieta, 

 Diachcuta and Trichochwta have always, or nearly always, 

 the seta3 throughout the body or of the posterior segments 

 arranged in an irregular fashion though there are onH 

 the usual eight per segment. The existence of peculiar 

 American forms in the West Indies and of peculiar 

 African forms in Madagascar is paralleled in other groups 

 of the animal kingdom. Pontoscolex it is true also occurs 

 in South America ; but it is so universally distributed a 

 form that its exact habitat is a matter of some doubt and 

 may as well be the West Indies as any other place. On 

 the hypothesis that the Geoscolicidse are comparatively 

 speaking a modern group, their total absence from the 







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CH. l] ACANTHODRILID.E. 65 



Australian region is a matter of moment, and recalls other 

 distributional facts. 



Not less interesting are the distributional facts con- 

 cerning the Acanthodrilidae. This family is divisible 

 into the following genera : Acanthodrilus t Benhamia, 

 Octochwtus, Diplocardia, Deinodrilus, Kerrici and Plagio- 

 chceta. The family itself is separable from all other 

 earthworms by the fact that, with the single exception 

 of the species Acanthodrilus monocystis, formerly placed 

 by me in a distinct genus Neodrilus, there are two pairs 

 of spermiducal glands, which have not, as they have in 

 nearly all other earthworms, a near connection with the 

 sperm ducts, but open actually on to different segments 

 from them ; these segments are XVII. and XIX. the 

 sperm ducts reaching the exterior by a pore situated 

 upon segment XVIII. The two pairs of glands as well as 

 their position are the distinguishing features of the family. 

 The further division of the family into genera is in some 

 respects not an altogether easy task. Deinodrilus is to be 

 at once distinguished by the fact that it has the unique 

 character of having twelve setse in each segment of the 

 body ; Plagiochceta has a larger number still, as in the 

 Perichsetidae ; but the genus could not be confounded with 

 a Perichsetid by reason of the fact that these setae are 

 disposed in pairs. Benhamia, Acanthodrilus and Octo- 

 chcetus are with more difficulty separable ; Benhamia and 

 Octochcetus have the excretory organs on the same plan 

 as those of the majority of the Perichaetidse ; they are 

 extremely numerous in each segment of the body and 

 open on to the exterior by very numerous pores on each 



B. Z. 5 




66 EARTHWORMS OF NEW ZEALAND. [CH. I 



segment. Acanthodrilus has the usual paired series of 

 nephridia. Kerria is a genus which is absolutely re- 

 stricted to America ; it is noteworthy on account of the 

 fact that it shows in several particulars evidence of 

 degeneration. Thus there is only a single pair of cal- 

 ciferous glands in the ninth segment, a character which 

 it shares with several of the more simplified genera of 

 Cryptodrilidae, such as Gordiodrilus ; the tubular glands 

 which open in common with the sperm duct are lined by 

 a single layer of cells instead of the thick layers so closely 

 resembling those of the clitellum which are found in the 

 majority of the remaining genera of earthworms. 



The three genera Octochcvtus, Deinodrilus and Plagio- 

 chceta are absolutely limited in range to New Zealand, 

 which may be considered to be the head-quarters of the 

 family, as it also possesses a fair share of the known 

 species of Accmthodrilus. Only three species of the latter 

 genus are found in Australia, and it is a noteworthy fact 

 that these three exist in Queensland and the neighbourhood 

 of Torres' Straits, on the side in fact which is turned towards 

 New Zealand and which has been probably at one time, 

 no doubt remote, joined to New Zealand. The remaining 

 species of Acanthodrilus are with a very few exceptions 

 inhabitants of the more southern regions of the South 

 American continent. They abound in Patagonia; but 

 they do not, on the east side of that continent, get 

 further north than Montevideo ; on the other hand in 

 Chili the genus extends considerably further north. The 

 exceptions that have just been referred to relate to 

 Kerguelen, Marion Island, the Cape of Good Hope, and 




CH. I] ETHIOPIAN EARTHWORMS. 67 



New Caledonia; in all of these countries there is one 

 species apiece of Acanthodrilus. This genus is unusual 

 though not unique among earthworms by reason of the 

 fact that it is largely aquatic in habit though mainly 

 terrestrial ; even the same species, as for example Acan- 

 thodrilus georgianus, may be at once aquatic and terrestrial. 

 This naturally adds to their facility for dispersal. The 

 genus Benhamia is almost entirely African, that is to say 

 " Ethiopian," in range ; it is true that one species, 

 Benhamia bolavi, has been met with in Europe ; but there 

 can be hardly any doubt that this species has been 

 accidentally imported ; there are also two or three species 

 in Mexico and the East Indies ; Dr Michaelsen thinks that 

 these owe their presence in the countries mentioned to 

 the effects of commerce and not to their own unaided 

 exertions. Finally in North America there is the singular 

 and somewhat aberrant genus Diplocardia, which consists 

 of but a single species. 



The most remarkable case of a restricted distribution 

 among the Oligochseta is the family EudrilidaB, which with 

 the single exception of the genus Eudrilus is not to be 

 met with outside of the Ethiopian region. As this genus 

 Eudrilus is one of the commonest forms in gatherings of 

 earthworms from several parts of the world, and as the 

 species found outside Africa do not differ specifically, I am 

 disposed to regard Africa as the proper home of this genus 

 also, and to look upon the exotic specimens as having been 

 accidentally carried thither. So far as our present know- 

 ledge goes, there are no forms outside of Africa which show 

 any particular resemblance to the EudrilidaB. This family 



52 




68 RANGE OF CRYPTODRILIDJS. [CH. I 



is marked out from all others by the fact that the ovaries 

 are nearly always contained in special sacs, which are 

 developed at the expense of the septa, and whose cavities 



therefore are true body cavities; and that these sacs 



4 



communicate with the exterior by the oviducts or by 

 special orifices or by both. In several genera the neph- 

 ridia, which are, as in the Lumbricidae, paired structures, 

 a pair to each segment of the body, branch copiously in 

 the thickness of the body wall, opening on to the exterior 

 by many pores in a single segment. There are other 

 peculiarities of structure which mark out the Eudrilidse 

 as one of the most isolated of families and therefore the 

 Ethiopian region as, from the point of view of its earthworm 

 inhabitants, one of the most peculiar of regions. It is 

 noteworthy, seeing that recently many of the West African 

 animals for example the Chimpanzees have been shown 

 to extend into East Africa, that the genera of earthworms 

 belonging to this family are not common to both sides of 

 the continent. We have on the west coast the genera 

 HeliodriluSy Hypriodrilus and Lybiodrilus among others ; 

 on the east coast Stuhlmannia, Polytoreatus, Eudriloides 

 and NotykuSj &c. &c. 



The family Cryptodrilidse is as has been already re- 

 marked nearly cosmopolitan. But the various genera of 

 which the family is made up are none of them of so wide 

 a range. Most of the principal regions have their peculiar 

 genera ; but the South American forms range also into New 

 Zealand. These species belong to the genus Microscolex 

 which occupies pretty nearly the whole of the South 

 American continent and the warmer parts of the Nearctic 




CH. l] MICROSCOLEX AXD OTHER GENERA. 69 



region. There are altogether sorne nineteen species of the 

 genus of which those that are not American are from New 

 Zealand ; two species are Algerian, and they are closely 

 allied to two American forms that have been met with in 

 Australia, in Italy, and in the island of Teneriffe. This 

 unusually wide range of the species in question seems to be 

 possibly another case of accidental importation by man. In 

 North America there are a few species assigned by Dr 

 Benham and Dr Eisen to the two genera Plutellus and 

 Argilophilus which I cannot differentiate from the purely 

 Australian genus Megascolides, a genus which contains one 

 of the largest earthworms at present known the giant 

 earthworm of Gippsland a creature which grows to a length 

 of six feet. In addition to this genus, which just gets into 

 New Zealand with a single species, Australia has limited 

 to itself the genera Cryptodrilus, Die/aster and Trinephrus\ 

 the latter genus I have thought it advisable to separate 

 from Cryptodrilus on account of the extraordinary fact 

 that its members have in each segment of the body three 

 pairs of nephridia. The division of the genera of Australian 

 Cryptodrilidae is however a matter of the greatest difficulty. 

 In any case it appears to be clear that with the exceptions 

 mentioned these genera do not extend beyond the Austra- 

 lian region and hardly beyond Australia itself. The 

 Oriental region is also fairly well off in worms belonging 

 to this family which are referable to the genera Deodrilus, 

 Typhceus, Microdrilus. Africa has several peculiar forms, 

 including Millsonia, Gordiodrilus and two species which 

 Michaelsen has referred to my Fijian genus Dichogaster, 

 but which may be really members of a different genus ; at 




70 MARINE EARTHWORMS. [CH. I 



present our knowledge of their anatomy is not sufficient 

 to decide the point definitely. In America besides the 

 genus Microscolex already described we have the bulk of 

 the species of the semi-aquatic genus Ocnerodrilus, also 

 found in Tropical Africa, and a species or two of the genus 

 Pontodrilus, which is like no other earthworms except the 

 ubiquitous genus Pontoscolex in living among the debris of 

 sea-weed on the sea-shore. The other species of this genus 

 live respectively in the Aru Islands, on the shores of the 

 Mediterranean, and the North Sea, affording an example 

 of the frequently wide range of forms whose habitat is a 

 narrow area. This family of earthworms is one that is so 

 difficult to classify in a satisfactory manner that it is not 

 wise to draw any conclusions from its range except to 

 point out the similarity between South America and New 

 Zealand. 




CHAPTER II. 



i 



ZOOLOGICAL GEOGRAPHY. 



IN the preceding chapter a few of the more salient 

 facts in the distribution of animals have been detailed. 

 We can define an animal by its geographical position as 

 much as by its structure. It follows that the converse is 

 equally true ; each country has its own special inhabitants. 

 One tract of country can be defined by its fauna and flora 

 and thus distinguished from another tract of country. 



A passage across the Straits of Dover lands us in a 

 country which would seem at first sight to agree absolutely 

 with our own in its animal inhabitants ; a prolonged 

 residence would however reveal the existence of a few 

 species of animals not met with in Great Britain ; but 

 the general facies of the fauna would withstand the most 

 prolonged scrutiny with a view to detecting differences. 



We may journey across the entire continent of Europe 

 without leaving a fauna generally like that which we have 

 at home ; even the traveller in Japan will at once recog- 

 nize many animals which are either the same or very 

 closely allied to those with which he is familiar at home. 




72 ZOOLOGICAL REGIONS. [CH. II 



But there are greater differences between Great Britain 

 and Japan than between France and Great Britain. 



In fact the more remote the tracts of country are 

 from each other, the more diverse are their faunas. But 

 there is no accurate balancing of distance and diversity of 

 fauna possible ; a journey into Central Africa, shorter by 

 hundreds of miles than that to Japan, will bring the 

 traveller into contact with forms of life altogether 

 different from those which occur in these islands. The 

 elephant, the giraffe, and the anthropoid apes will testify 

 to the change which has taken place in a journey com- 

 paratively so short. In the Eastern Archipelago are two 

 islands only separated by a few miles, Bali and Lombok ; 

 traversing this narrow strait will produce an entire change 

 in the fauna, greater even than that which is experienced 

 by the traveller from Europe to Tropical Africa. An 

 entirely new race of mammals will be met with, the 

 marsupials ; while the apes, carnivora, and ungulate 

 animals of the western parts of the Indian Archipelago 

 entirely vanish or get exceedingly rare. 



Mr Sclater's regions. 



The first real attempt to divide the earth into regions 

 corresponding with the range of its inhabitants is that of 

 Mr Sclater 1 . 



His results were obtained entirely from a consideration 

 of the Passerine and some of the Picarian birds. Never- 

 theless the regions thus formed were found applicable to 



1 Journ. Linn. Soc., 1857. 




CH. II] REGIONS OF MR SCLATER. 73 



other groups and they have been for the most part 

 accepted. Mr Wallace more than anyone else has written 

 much in their support. 



It has however been insisted upon by many that these 

 regions do not fit in with the facts of distribution of other 

 groups. That their applicability to the Passerines and to 

 those groups which they do suit is due to the fact that 

 these groups are modern and that there has in all proba- 

 bility not been much change in the relative distribution 

 of land and sea since the groups in question came into 

 existence. These regions however are more particularly 

 unsuitable to older groups, which retain, so to speak, the 

 impression of earlier conditions of land and sea. So much 

 so that the agreement or non-agreement of a particular 

 group with the regions instituted by Mr Sclater are in 

 some degree a test of its antiquity. Even in the more 

 modern groups the resemblance is not always striking. 

 Nor could we really expect that it would be ; for a close 

 resemblance would imply a similar place of origin, an 

 identical series of migrations and backward migrations, 

 and a susceptibility to precisely the same barriers and 

 hindrances ; these assumptions are evidently not to be 

 thought of as well founded. So complicated are the 

 conditions which govern the restrictions to migration and 

 the facilitation of migration that it would be impossible 

 to conceive of there being in any one case close corre- 

 spondence with another case. While therefore we cannot 

 expect to find a series of cut and dried regions which shall 

 express the known facts of distribution of all terrestrial 

 groups, it is of some use to have a convenient system 




74 DISTRIBUTION OF MAMMALS. [CH. II 



whereby the facts of distribution may be at once and with 

 ease appreciated. 



Mr Sclater founded his regions mainly upon the dis- 

 tribution of Passerine birds; but in a subsequent lecture 1 

 upon the geographical distribution of the Mammalia he 

 applied the same regions for the purposes of tabulating 

 the distribution of that group of animals also. In 

 considering the distribution of the existing Mammalia 

 four salient facts are at once apparent. 



(1) Australia has both Monotremes and Marsupials. 



(2) America has Marsupials but no Monotremes. 



(3) The remainder of the world has Monodelphian 

 Mammals only. 



(4) New Zealand has no Mammals at all. 



On this basis Mr Sclater divided the world as follows : 



I. Land where Monodelphs only occur ; no Marsupials 

 or Monotremes. Europe, Asia, Africa, Asiatic islands 

 down to Wallace's line, North America 2 . This land may 

 be called Arctogcea. 



II. Land where Monodelphs and Marsupials occur; 

 no Monotremes. America south of the Isthmus of 

 Tehuantepec. This land may be called Dendrogcea. 



III. Land where Marsupials prevail ; no Monodelphs 

 but rodents and bats; Monotremes. Australia. This 

 may be called Antarctogcea. 



IV. Land without Mammals (except bats) 3 . New 



1 "The Geographical Distribution of Mammals." Science Lectures 

 for the People, 1874. 



2 The common Opossum ranges however into this region. 



3 For a possible exception see below. 




CH. n] MR HUXLEY'S REGIONS. 75 



Zealand and the Pacific islands. This land may be called 

 Ornithogcea. 



Arctogasa is then subdivided into the well known 

 Palaearctic, Ethiopian, Indian and Nearctic regions. But 

 it is pointed out that these sections are not equal to the 

 remaining and undivided Antarctogsea and Dendrogsea. 

 The fourth section, Ornithogaea, is necessarily left out of 

 consideration altogether, as it contains no Mammals (with 

 a trifling exception or two). A better name for this 

 division of the earth's surface is perhaps that suggested 

 by Prof. Lankester, viz. Atheriogsea, since it expresses the 

 cardinal fact in its zoogeography : which is not the posses- 

 sion of a rich bird fauna but the absence of an indigenous 

 Mammal fauna. 



Mr Huxley's regions. 



A study of the distribution of the Alectoromorpha led 

 Prof. Huxley to suggest a different division of the world 

 into regions. 



The Peristeropodes (the Cracidse and Megapodidae) are 

 confined to a range of country which includes continental 

 Australia and some of the islands to the north, along with 

 South and Central America; this tract of the earth's 

 surface he termed Notogaea, the part lying to the north 

 being called Arctogaaa. Arctogaea is tenanted by the 

 following families of birds which are at most but poorly 

 represented to the south of the line already mentioned : 

 the Pteroclidas, Otidise, Gruidse, Vulturidae, Upupidse and 

 Bucerotidse. This area is almost coincident with the 

 range of the Insectivora, and it is the head-quarters of the 




76 NOTOG^A AND AHCTOG^A. [CH. II 



Ungulata. Ganoid fishes are not found outside it. On 

 the other hand the southern region has all the Ratitse 

 (except Struthio), the Tinamous, the American Vultures 

 (Cathartidas), the bulk of the Pigeons and the Parrots 

 including the most peculiar forms of both, and nearly all 

 the Trochilidse and Aptenodytida?. Such remarkable and 

 isolated types of birds as the Palamedeidae, Psophiidae, 

 Cariamidaa and Opisthocomidse are also confined to it. 

 Among Mammals it is characterised by the Marsupialia, 

 the Platyrrhine monkeys, the Monotremata, and most of 

 the Edentata. It is poor in Ungulata. 



This region of Notogsea is again divided by Prof. 

 Huxley into three divisions, which he names Austro- 

 Columbia, Australia and New Zealand. 



The most obvious criticism to apply to these, and 

 which has been applied, is that they are quite out of 

 proportion ; this is particularly the case with New Zealand, 

 which has so few types of great importance as compared 

 with Austro-Columbia. I do not however enter into any 

 detailed criticism since the actual way in which the earth 

 is divided up is so largely a matter of convenience as is 

 admitted on all hands. 



Other suggested regions. 



Some have wished to make a separate region of Mada- 

 gascar, which has unquestionably a large number of 

 peculiar types. Arctic and Antarctic regions commend 

 themselves to many. 



Quite the most unsatisfactory region, in my opinion, 




CH. II] POLYNESIAN REGION. 77 



that has been proposed is the Polynesian adopted by Prof. 

 Heilprin 1 . This is meant to include the scattered islands 

 to the east of Australia, comprised between lat. 20 N. 

 and lat. 40 S. Prof. Heilprin admits that this region is 

 defined " more by negative than by positive characters," a 

 necessary admission, though not convincing of the justice 

 of framing it. He distinguishes it by the absence of all 

 Mammalia except a few bats, Pteropidse and Vespertilio- 

 nidse. The birds include no special families excepting 

 only the Rhinochetidae and the Didunculidse and Drepani- 

 didaB. All the other families are either exclusively 

 Australian types or are birds of a wider range, including 

 Australia. Among lizards the most remarkable form is 

 the Iguanid Brachylophus from the Fijis. The same 

 islands harbour three species belonging to the frog genus 

 Cornufer and a toad, Bufo dialophus. If he includes, 

 which appears probable though there is no definite 

 statement upon the point, the Solomon Islands in this 

 group, we can add to his list as distinctive of the " region ''' 

 the huge Ranci yuppyi, a species of the Marsupial genus 

 Cuscus, besides a crocodile, several snakes, and some more 

 lizards and Amphibia, There is no remarkable assemblage 

 of peculiar genera such as differentiate the other regions ; 

 the differences that do characterise this so-called region 

 are merely due to the isolation of the different islands 

 which are either (as in the case of the Solomon Islands 

 according to Blanford) remnants of former land connection 

 with Australia or New Guinea, or oceanic islands which 

 have been populated from the nearest mainland, i.e. 

 1 Called Nesogsea by Prof. Gill, Proc. Biol. Soc. Washington, Vol. i. 




78 HOLARCTIC REGION. [CH. II 



Australia. That there should be peculiar genera is quite 

 in accord with both these modes of origin ; but the fewness 

 of the peculiar genera and their alliance with Australian 

 forms seems to render it necessary to place the entire 

 Polynesian realm within the Australian, and at most to 

 regard it with Mr Wallace as a subregion (exclusive in 

 this case of the Solomons). 



Mr Sclater's regions the most convenient. 



The question is, What system shall we adopt ? 



The ideal system would be one which agreed entirely 

 with the distribution of land and sea and their inhabitants; 

 but that is unfortunately impracticable. The next best 

 is obviously the plan to try ; and Mr Sclater's regions are, 

 with an exception here and there, coincident with the 

 continents and larger islands. The great thing is not to 

 dispute the standard to be taken, but to agree in holding 

 to one standard. As a mere matter of convenience it is 

 immaterial whether we join Europe, Asia, and North 

 America into one Holarctic region, or use the current 

 terms of Nearctic and Palaearctic for the Old and New 

 World divisions of this extensive tract. What we want 

 to do is to find a common outline into which the details 

 can be inserted. Mr Wallace in a recent lecture upon 

 the regions most convenient for adoption 1 urges the 

 retention of the Sclaterian regions for the following three 

 principal reasons : 



(1) They are founded upon and approximate to the 

 great primary divisions of the earth, which there is reason 



1 Nature, 1894. 




CH. Il] REASONS FOR ADOPTING MR SCLATER'S REGIONS. 79 



to believe have been permanent during considerable 

 geological periods. 



(2) They are rich and varied in all the main types of 

 life. 



(3) They possess great individuality ; whether ex- 

 hibited by the possession of numerous peculiar species, 

 genera, or families, or by the entire absence of genera or 

 families which are abundant and wide-spread in some of 

 the adjacent regions. 



Mr Wallace admits that these regions are not quite 

 perfect in all of these requirements, but they are more so 

 than any other arrangement which has been devised. The 

 Nearctic for instance is the poorest and the Neotropical 

 region is the richest ; there is not an absolute equality 

 between any two ; nor could the world be split up so as to 

 attain to that desirable end. It is a matter of the very 

 smallest importance to wrangle over the division which is 

 most natural ; as Mr Wallace says " there is no question 

 of who is right and who is wrong in the naming and 

 grouping of these regions or of determining what are the 

 true primary regions. All proposed regions are from 

 some points of view natural but the whole question of 

 their grouping and nomenclature is one of convenience 

 and utility in relation to the object aimed at." 



It is clear that if our Zoological regions were to be 

 constituted on the evidence afforded by the groups of 

 animals whose range has been briefly sketched in its 

 main outlines on previous pages they would not agree 

 entirely with those of Mr Sclater or with each other. 



The Herpetological regions show a marked difference 




80 DIFFERENT DIVISIONS OF EARTH'S SURFACE. [CH. II 



in the first place between the Old and New Worlds : Asia 

 and Australia are nearer together than either of them is 

 to Africa ; and Africa is more nearly akin to Europe than 

 to any other region. New Zealand forms a region quite 

 apart from the others. 



The earthworms on the other hand do not show so 

 marked a distinction between the Old and the New 

 Worlds ; indeed they offer the best evidence of any group 

 in favour of the Holarctic region. The Ethiopian region 

 is very distinct, perhaps the most distinct of all. The 

 Australian region is barely separable from the Oriental. 

 It is quite necessary, in order to emphasise the facts 

 of distribution in this group, to constitute an Antarctic 

 region embracing New Zealand and Patagonia. 



The Batrachians are again quite different from either 

 of the other two groups considered. The Neotropical and 

 the Australian really form one big region ; so also do the 

 Ethiopian and the Oriental ; on the other hand the 

 Nearctic and the PalaBarctic are quite distinct ; there can 

 be no question here of a Holarctic realm. 



To express in a graphic form the distribution of the 

 land Planarians is a simpler matter than in the case of 

 any of the other groups. 



The following pages contain schemes of the distribu- 

 tion of some of these groups which are compared with the 

 Insecta whose range in space and peculiarities of distribu- 

 tion I have not treated of at all. The diagrams of most of 

 these are taken from M. Trouessart's book already referred 

 to more than once and they represent the latest and most 

 reliable information from specialists on the several groups. 




CH. II] 



PLANS OF DISTRIBUTION. 

 REPTILES 



81 



Nearctic 



Neotropical 



Neotropical 



Europe 



Africa 



a 



Asia 



Australia 



and 

 Polynesia 



EARTHWORMS 



Holarctic 



Ethiopia 



Oriental 



Australia 



BATRACHIA 



Nearctic 



Neotropical 



Ethiop. 



Oriental 



Australia 



1 a Madagascar, b New Zealand, c Patagonia. 

 B. Z. Q 




82 



USE OF BIRDS FOR DEFINING REGIONS. [CH. II 



COLEOPTERA 



Holarctic 



Brazil 



g Polynesia 



o> 



Indo- 

 African 



Patagonia 



Australia 



Upon what group then shall we found our divisions of 

 the earth's surface ? 



The great objection to the birds is that they can 

 fly and are therefore independent of most barriers ; with 

 them temperature, food and pre-occupation of the ground 

 must be the chief limitations to universal range. More- 

 over it will be remembered that this group contains the 

 largest number of cosmopolitan genera and species. All 

 this tends to throw the claims of the birds into the 

 background. Against their exclusive use also is the fact 

 that they are a modern race, and would therefore at best 

 only indicate the present arrangement of land and sea. 

 At the furthest the birds go back to the Jurassic period ; 

 while the Carinate birds (speaking zoologically and not 

 etymologically) are not of greater age than the Tertiary 

 period. All curves of development show that birds are now 

 in the ascendant and that they have risen rapidly into 

 prominence. To this is due the variance of opinions 




CH. II] MOLLUSCA AND ZOOLOGICAL REGIONS. 83 



that prevail with regard to their proper classification. 

 So intimately connected are the various types that it is 

 difficult to define the groups ; and all classification has to 

 go upon that most unsatisfactory plan, the averaging of a 

 number of structural characters. A thinning out of the 

 numberless existing genera might reveal the main lines 

 of ascent just as the branches of a tree stand out more 

 plainly when they are denuded of the leaves. I have 

 attempted to show elsewhere (p. 81, 82) that it is difficult to 

 get any real justification for the generally adopted regions 

 by the study of the range of different families. All that 

 can be said in most cases is that the various regions have 

 each a certain number of peculiar genera and families; 

 but those facts lose value from the impossibility of 

 making definite statements about the mutual affinities 

 of the genera in question. The Gallinaceous birds which 

 are less endowed with power of wing than many other 

 groups offer the best evidence of a connection between 

 structure and distribution. So too the Struthious birds. 



Land Mollusca would appear on many grounds to be 

 exceedingly valuable as furnishing evidence in favour 

 of ancient land connections. 



In an interesting paper Prof. Kobelt, a great authority 

 upon the group, urges their claims to be put in the fore- 

 front of animals useful for this purpose. 



There is however more than one serious objection 

 to their use. As Mr Blanford points out, we are not 

 at present in a very forward state of knowledge as to 

 what conchologists term " the animal " ; the anatomy 

 of the group is for a large part ignored by those even who 



62 




84 CHARACTERS OF MOLLUSCA. [CH. II 



make the group their special study. The relationships 

 therefore of the different genera is in many cases obscure. 

 They can therefore not be made use of in a strictly 

 scientific comparison of the faunas of various parts of the 

 world. We know how varied may be the structure of 

 other animals even belonging to the same group under 

 a superficial similarity ; for example the genus Doriopsis 

 among the Nudibranchs differs from the genus Doris 

 (sensu lato) by the total absence of that most character- 

 istic molluscan organ the odontophore ; and yet with this 

 important dissimilarity it would be impossible to separate 

 the two genera by any marked external characters. 

 Were one totally unacquainted with their internal 

 structure the Brachiopods and Lamellibranchs might be, 

 as they have been in the past, associated closely together. 

 Analogous differences may separate some of the genera 

 of Pulmonata whose anatomy is not known. 



In the second place they are very capable in some 

 way or other of crossing the ocean, for we find them in 

 oceanic islands which cannot have been stocked inde- 

 pendently with them. Mr Wallace remarks that " they 

 have no means of passing over the sea but such as are 

 very rare and exceptional." He quotes however Darwin's 

 experiment to the effect that a Roman snail lived after 

 immersion in salt water for twenty days. For further 

 examples of the ways in which the terrestrial Mollusca 

 can cross the sea the reader is referred to a later 

 chapter. 



If it were not for these objections the land Mollusca 

 would be a most important group ; they are extremely 




CH. II] MAMMALS AND ZOOLOGICAL REGIONS. 85 



ancient, the existing genera Pupa and Zonites going back 

 to Carboniferous times. 



Mr Wallace urges the superior claims of Mammals 

 upon whose distribution to found Zoological regions. He 

 thinks that they are best qualified " to exhibit by their 

 existing distribution the past changes and present physical 

 condition of the earth's surface." 



The reasons for this opinion are according to Mi- 

 Wallace the following: (1) They are dependent for 

 their means of dispersal upon continuity of land. At 

 least wide seas would be impassable. (2) They are (with 

 the exception of the bats which fly and might therefore be 

 subject to gales, and the mouse tribe which might be are 

 in fact conveyed in ships) too large to be carried acci- 

 dentally across seas which they could not traverse by 

 their own unaided efforts. (3) Again they are so highly 

 organised as to be largely independent of other animals : 

 though both purely carnivorous and purely vegetarian 

 forms exist there is for the most part no dependence 

 upon any particular kind of animal or plant as food, such 

 as we meet with for example among the insects. Or 

 where there is a restriction in the matter of diet as in the 

 case of the anteaters both of the old and new worlds the 

 food is universally found. (4) The mammalia form a group 

 which is fairly well known anatomically, we can therefore 

 form a tolerably correct judgment as to their mutual 

 relationships. That this is the case is shown by the 

 absence of any differences of opinion as to the outlines 

 of the main subdivisions of the family. (5) The last 

 argument favourable to the Mammalia is the fact that 




86 PAST HISTORY OF MAMMALS. [CH. II 



we have a better knowledge of extinct forms than we 

 have of any other existing group. It is perfectly true 

 that this knowledge will bear increasing and that it is 

 practically limited to the extinct genera of Europe and 

 North America with certain parts of South America and 

 India. But after all compared with other groups the 

 knowledge is undoubtedly considerable. 



Though all this is perfectly true, yet the Mammalia 

 are by no means an ideally perfect group for these 

 purposes. 



In the first place they are a comparatively modern 

 group, dating back at the furthest to the triassic period. 

 They are therefore perhaps to be regarded as representa- 

 tives of the present state of affairs in land and sea. They 

 have for example in all probability never reached New 

 Zealand, between which and New Australia there may 

 very likely have been an ancient land connection some- 

 where in the early secondary period or even earlier. The 

 Mammalia also, although a comparatively modern race, are 

 a waning race ; as it has been said, we live in a world 

 which is as regards mammals zoologically impoverished. 

 This has brought about the existence (if the hibernicism 

 be allowed) of so many missing links. The Marsupials for 

 example, though called by Mr Huxley Metatheria and 

 believed by him and by others to stand midway between 

 the Monotremes and the higher Mammalia, with a more 

 near approximation to the latter, cannot be satisfactorily 

 tacked on to any particular group of the Eutheria. The 

 very fact that the living Mammalia can be so easily 

 classified, and that there is so little difference of opinion 




CH. Ill BEST GROUP FOR DEFINING REGIONS. 87 



-* v 



about the scheme of classification, shows the breaks that 

 exist between the various families. Though it is true that 

 we have a fair anatomical knowledge of the Mammalia, 

 yet there are plenty of lacunae ; the broad facts are 

 perhaps ascertained, but there are many details of im- 

 portance which require further elucidation. For instance 

 there is but little knowledge, and that purely osteological, 

 of the structural differences between the different kinds of 

 bears and cats. These two families have a wide distribu- 

 tion and it would be of great interest to know if for 

 example the muscular anatomy of the new world forms 

 is distinctive of them and different from that of the old 

 world genera or species. Besides much of our knowledge 

 of the Mammalia is limited to skins and horns, in many 

 cases necessarily. Unsuspected differences so constantly 

 turn up between superficially very similar forms, that 

 further knowledge is desirable. A noteworthy instance 

 are the discoveries by the late Prof. Garrod in the anatomy 

 of the soft parts of the rhinoceroses. 



On the whole, however, it is impossible to avoid agree- 

 ing with Mr Wallace that the Mammalia are the most 

 satisfactory group. And moreover the adoption of the 

 regions necessitated by the distribution of this group is 

 in harmony with the distribution of some other groups 

 and does no great violence to distributional fact any- 

 where. 




88 PAL^ARCTIC REGION. [CII. IT 



The six Zoological regions of Mr Sclater. 



In the pages that follow I have purposely refrained 

 from a detailed account of the faunas of each ; much that 

 is not to be found in the present section will be found 

 elsewhere. I have here simply abstracted from Wallace 

 and other books a list of the genera absolutely confined to 

 each region, and given a few forms which are highly 

 characteristic of, though not absolutely confined to, each 

 region. 



I. The Palsearctic region. 



This region contains in the first place the whole of 

 Europe with the outlying islands of Iceland in the north 

 and down to the Cape de Verde islands in the south. 

 The north of Africa to the tropic of Cancer is included by 

 Mr Wallace, though others prolong the Palsearctic region 

 further to the south ; the Arabian peninsula is divided 

 into two approximately equal halves by the line of division 

 between the Palsearctic and the Ethiopian region. The 

 whole of the north of Asia including Japan belongs to this 

 region, which reaches the Arabian sea along the coast of 

 Persia. The delimitations of the Oriental region are along 

 the southern slopes of the Himalayas, Afghanistan and 

 Baluchistan going with the Palaearctic. In China the 

 limits of the Palsearctic region are at about Shanghai 

 on the coast. 



(i) Families of animals confined to the Palsearctic 

 region. 



None. 




CH. II] PAL^ARCTIC REGION. 89 



(ii) Genera confined to the region. 



Talpa; Scaptochirus ; Myogale; Scaptonyx ; Anu- 



rosorex (Moles). 



Lutronectes (an Otter) ; Meles (Badger). 

 Camelus ; Dama (Fallow deer); Capreolus (Roe 

 deer) ; Hydropotes, Lophotragus, Elapliodus (Cer- 

 vidae) ; Bos, Poephagus (Yak) ; Addax, Procapro 

 Saiga, Panthalops, Rapicapra (Antelopes) : 

 Capra (Goat tribe). 



Myoxus (Dormouse) ; Spalax (Rodentia). 

 Lnscinia, Accentor, Erithacus (Sylviidye); Panuws 

 (" Bearded tit ") ; Garrulus, Perisoreris (Jays) ; 

 Nucifraya (Nutcracker) ; Cyanocitta, Fregilm 

 (Chough); FringUla, Acanthis, Moniifringilla 

 (Finches). 



Perdix, Tetraogallus (Gallinacese). 

 Ibidorliynchus (Scolopacidae). 



The region is however also characterised by a large 

 number of forms which have their chief development- 

 therein, though they extend over its boundaries. 



The genus Phasianus is nearly confined to the region 

 and other allied genera such as Thaumalea the Golden 

 Pheasant, Ceriornis the Tragopan, and the Ipeyan Phea- 

 sant, Lophophorus, have their greatest development within 

 this region, though they do as a matter of fact cross its 

 border and pass into the Oriental region. 



A great many of the Mammalia are either specifically 

 identical with North American forms or are very near 

 indeed to them. The Aurochs and the Wapiti are hardly 

 if at all specifically different from Luhdorf 's deer and the 




90 PAL^ARCTIC AND NEARCTIC. [CH. It 



American bison. The grizzly bear, though it has received 

 the specific name of Ursus feroao, is barely distinguishable 

 from the brown bear Ursus arctos of Europe ; there is no 

 doubt at all about the identity of the reindeer, the elk, 

 the glutton and the arctic fox which are common to the 

 Nearctic and the Pataarctic regions. The lynx, wolf, 

 marten, beaver and marmot are forms common to both 

 regions without differences at all or showing differences 

 of the slightest possible kind. All these animals are 

 among the most characteristic of those inhabiting the 

 Pala3arctic region. The pouched rats Cricetomys are, as 

 has been recently shown by the leading authority upon 

 this group, Mr Thomas, hardly generically separable from 

 the American Hesperomys. The musk deer, Mosclms, and 

 the peculiar bear-like creatures Ailuropus and Ailurus are 

 not confined to the Palsearctic region ; they are as charac- 

 teristic of it however as they are of the Oriental region, in 

 which they also occur. Even the tiger so pre-eminently, 

 according to popular literature, a denizen of the tropics, 

 may be fairly counted as an inhabitant of the temperate 

 or even subarctic Pala3arctic region since it has been met 

 with so far north as the Amur. It is but recently that 

 there were similar resemblances between the fauna of the 

 western part of the PalaBarctic region with that of Africa ; 

 the hippopotamus, the Maltese elephants, the lion and 

 various other creatures have only lately become extin- 

 guished in this continent. While the mammoth of Siberia 

 and elsewhere is held by some to be the actual progenitor 

 of the Indian elephant, which is thought by them to hardly- 

 rank as a different species but to be rather a variety which 




CH. II] PAL^ARCTIC SUB-REGIONS. 91 



lias lost its hairy covering on becoming an inhabitant of a 

 hot climate. The hairy rhinoceros of Europe is another 

 case in point. 



The Palaearctic region is divided into (I) European, 

 (II) Mediterranean, (III) Siberian, (IV) Mantchurian 

 sub-regions. 



I. The European sub-region comprises Central and 

 Northern Europe. The only really peculiar genus is the 

 Desman, Myogale, found in the streams of the Pyrenees 

 and of Southern Russia. Many other Mammalia however 

 are highly characteristic of the sub-region, though not 

 positively confined to it. Such are the wolf, the mole, 

 the hedgehog, and the dormouse. Not a single genus 

 of birds is absolutely confined to the sub-region. But the 

 Wagtails, the Tits and the Reedling, Panurus 1 , are genera 

 which are more abundant in this part of the world than 

 elsewhere. 



II. The Mediterranean sub-region, as might be in- 

 ferred from its warmer climate, is by far the richest portion 

 of the Palsearctic region. Besides that part of Europe 

 bordering upon the Mediterranean Sea, it includes the 

 north of Africa, down to the desert of Sahara, Persia and 

 Baluchistan. Among Mammalia the Fallow deer (Dama) 

 is peculiar to the sub-region ; so too are Psammomys and 

 Ctenodactylus, two genera of rodents. The Civet of the 

 south of France and South Europe generally, the Porcupine 

 and others are among the characteristic though not 

 peculiar genera. These and some others show the African 

 affinities of the Mediterranean sub-region. The Hywna 



1 Sometimes (and inaccurately) called the "Bearded tit." 




92 PAL^EARCTIC SUB-REGIONS. [CH. II 



and the Lion point to the same transitional character. 

 Among birds two warblers, Lusciniola and Pyrophthalma, 

 iire peculiar. 



III. The Siberian sub-region includes the whole of 

 Northern Asia. Of Mammals the yak and two antelopes, 

 Procapra and Pantlialops, are confined to it ; the mole 

 Nectogale is another peculiar form and completes the list 

 of genera that are found here and in none of the other 

 sub-regions. The musk deer however, Moschus, is nearly 

 confined to the sub-region, while many Arctic animals, such 

 as the sable, the glutton, and the reindeer are highly 

 characteristic of it; the two latter as already mentioned 

 also extending their range into the Nearctic region. 

 Among birds there are few peculiar forms. The only 

 genus that is " most decidedly " confined to the region is a 

 genus of Starlings Podoces. 



IV. The Mantchurian sub-region, bordering as it does 

 upon the tropics, is rich when compared with other parts 

 of the Palsearctic region. It includes all Japan besides 

 Corea and other parts of China. Some of the peculiar 

 deer, discovered by Pere David and his associates, are 

 peculiar to this sub-region. Such are Hydropotes and 

 Elaphodm. The curious Nyctereutes and the carnivore 

 jEluropus are also peculiar forms or nearly so. The 

 former is often called the "raccoon-like dog"; the latter 

 genus is allied to the Panda, ^Elurus. Both of these 

 occur also in the Oriental region. A genus of Otters, 

 Lutronectes, is also peculiar, and there are a few other 

 genera which are found in this sub-region and not in the 

 other sub-regions of the Palaearctic region. The birds are 




CH. II] NEARCTIC REGION. 93 



represented by an abundant variety of species ; but as 

 many of them are common to this and to the Oriental 

 region which borders upon it, it is a little difficult to 

 disentangle the faunas of the two. Some of the mag- 

 nificent pheasants of the East, the genera Lophophorus, 

 Pucrasia, Thaumalea, and Crossoptilon, are characteristic ; 

 but these have already been mentioned as among the 

 birds characteristic of the region as a whole. There are 

 also species of Ceriornis and Phasianus. 



II. The Nearctic region. 



This region consists of the whole of North America, 

 together with a portion of Mexico, into which, according to 

 Mr Wallace's map of the region, it sends a narrow tongue 

 along the central mountain range. As Mr Wallace has 

 pointed out, the greatest width of the continent in the 

 more arctic parts of it and its narrowness where the 

 climate becomes more congenial is largely responsible for 

 the comparative poverty of the fauna. 



List of families peculiar to the Nearctic region. 



Saccomyidcv (Pouched rats), Haploodontidcu (Ro- 

 dentia). 



Chamceidcv (Passerines). 



Genera peculiar to the region. 



Synotus, Autrozous (Bats). 

 Condylura, Scapanus, Scalops (Moles). 

 Latax, Taxidea (Garni vora). 

 Antilocapra, Ovibus, Haplocerus (Bovida3). 




94 NEARCTIC REGION. [CH. II 



Neotoma, Sigmodon, Jaculus, Cynomys, Erethizon 

 ( Rodent ia). 



Salpinctes, Catherpes, Gymnokitta Picicorvus, Cent- 

 ronya', Neocorys. &c. (Passeres). 



Ectopistes (Columbidse). 



Pilohela (Scolopacidse). 



Highly characteristic of the region, among the Mam- 

 malia, are in the first place the bison and the grizzly 

 bear ; it is not quite certain, as I have already mentioned 

 under the description of the Palasarctic region, whether 

 these animals are specifically distinct from what are at 

 the very least close allies in Europe and Asia. But if so 

 the bison, now limited to a single herd from previously 

 existing thousands, is a noteworthy type of American life, 

 no less than is the formidable "grizzly." Bassaris, an 

 animal now known to be allied to the Raccoons, but 

 formerly placed in a different division of the Carnivora, is 

 one of the numerous forms that are so common to the 

 Nearctic and Neotropical regions, but has a larger range 

 in the former. The Puma and the Skunks are other 

 examples of animals which extend northwards from the 

 South American continent. Among birds, humming birds 

 and various members of the families Mniotiltidae, Vireo- 

 nidse and CserebidaB are examples of Neotropical forms 

 which also extend into the North American continent. 

 The same is the case with the Tanagers and several 

 South American genera of FringillidaB. The black cuckoo 

 with a deep bill, the ani, Crotophaga, is also met with in 

 North America, though more characteristic of South 

 America. 




CH. II] NEARCTIC REGION. 95 



A closer resemblance between the Nearctic and the 

 Palsearctic regions than that which obtains between, say 

 the Neotropical and the Ethiopian, would be expected on 

 the theory of the polar origin of life. That there is a 

 close resemblance has also some relation to the great 

 similarity in climate and physical conditions between the 

 two regions. But the question now for consideration 

 is whether the similarity is such as to warrant the 

 inclusion of the two in one Holarctic realm, as is 

 contended by Dr Heilprin and Prof. Newton. Dr Wallace 

 decidedly thinks not ; and his reasons for this opposition 

 are set forth in a special paper devoted to the question 1 . 

 It appears from his tables that there are 43 genera of 

 Mammals which are found in the Palaearctic region but 

 not in the Nearctic. On the other hand 39 are peculiar 

 to the Nearctic; 31 are common to both regions. 

 These estimates, even when slightly edited, as will be 

 indicated immediately, leave a respectable balance of 

 forms peculiar to each region; doubtless the number of 

 forms is poor when compared with other regions ; but it 

 must be borne in mind that these two temperate regions 

 do not abound in Mammalian life as do the more tropical 

 parts of the earth's surface. Of the 39 genera peculiar 

 to the Nearctic region seven may be not unfairly deducted 

 in making a final estimate as being largely, if not to a 

 greater extent, Central or South American, i.e. Neo- 

 tropical, also. The peccary, for example, is an animal 

 which is rather characteristic of the Neotropical than the 

 Nearctic region. The most striking argument however 



1 Natural Science, June, 1894. 




( JG NEARCTIC SUB-REGIONS. [CH. II 



for the reunion of the regions is afforded by the con- 

 sideration that out of the 31 genera that they have in 

 common it is only possible to withdraw three, as being- 

 aquatic and therefore having a range of less significance, 

 and four which are exclusively or largely Arctic. Removing 

 in addition four genera of ubiquitous bats there are left 

 16 genera which are common to the two regions. This 

 calculation is made on the basis of genera admitted by 

 Mr Wallace ; on a more liberal estimate of what is meant 

 by a genus the number of genera would of course be 

 increased. 



The Nearctic region is usually divided into the four 

 following sub-regions: (I) Calif ornian, (II) Rocky Mountain, 

 (III) Alleghany, (IV) Canadian. 



I. Calif ornian sub-region. This includes besides Cali- 

 fornia a considerable part of British Columbia. It has 

 several peculiar genera of Mammals. Among them are 

 Enhydra a sea otter, Urotrichus a mole and Neosorex a 

 shrew. Haploodon, a rat-like rodent, is peculiar to this 

 sub-region, as are also the only North American repre- 

 sentatives of the bat families Phyllostomidae and Nocti- 

 lionida?. The birds also embrace some peculiar forms. 

 The " road runner " Geococcyx and the aberrant Passerine 

 Chamcea, which Dr Shufeldt places near to the Tits, are 

 found here and nowhere else in the region. There are 

 other characteristic birds, but few that are absolutely 

 confined to the sub-region. 



II. Central or Rocky Mountain sub-region. The " big- 

 horn" sheep (Ovis montana), the Antilocapra and the goat 

 Haploceros are among the most characteristic Ungulates 




CH. II] CANADIAN SUB-REGION. 97 



confined to the sub-region. The bison so reduced in 

 numbers now-a-days is almost confined to the Rocky 

 Mountain sub-region. The prairie dog, Cynomys, a close 

 ally of the marmot, is restricted to the sub-region. Birds 

 contribute their quota toward distinguishing the sub-region 

 from those which border upon it. But they are genera 

 and not families. Among them may be mentioned the 

 following: Salpinctes, a wren, Poospiza, a finch, and Pe- 

 diocoetes, a grouse. 



III. Eastern or Alleghany sub-region. Mr Wallace 

 remarks that this sub-region " contains examples of all 

 that is most characteristic of Nearctic zoology." But 

 there is only one genus of Mammalia that is absolutely 

 confined to it. This is Condylura, the star-nosed mole. 

 Only 30 birds are mentioned by Wallace as peculiar to 

 the region among non- migrants. 



IV. The Subarctic or Canadian sub-region. This 

 naturally presents many features of resemblance to the 

 arctic parts of the Palaearctic region. It is charac- 

 terised for example by such forms as the glutton, reindeer 

 and elk, which pass into the Palsearctic region also. 

 The musk deer however, Ovibos, is limited to this region, 

 having apparently been a few times found outside of it in 

 the Palsearctic region. The birds though numerous are 

 not so peculiar: it upsets the current notions as to the 

 tropical habits of the humming-birds to learn that a 

 species, Selaspliorus rufus, breeds in Alaska. 



B. Z. 




98 ETHIOPIAN REGION. [CH. II 



III. The Ethiopian region. 



The Ethiopian region consists of all Tropical and 

 South Africa, from about the Tropic of Capricorn (see 

 Palsearctic region) ; it also includes the island of Mada- 

 gascar and the adjacent Mascarene islands. 



(i) Families peculiar to the Ethiopian region. 



Chiromyidce (Lemur). 



Potamogalidce, Chrysochloridce ( Insect ivora). 



Cryptoproctidce, Protelidce (Carnivora). 



Hippopotamidce, Camelopardalidce (Ungulata). 



Orycteropodidcu (Edentata). 



Buphagidce, Philepittidce (Passeres). 



Musophagidce, Collides, Leptosomidce, Irrisoridce 



(Picarians). 



Serpentariidce (Accipitres). 

 Struthionidce. 



(ii) Genera peculiar to the region. 



Gorilla, Anthropopithecus, Colobus, Cercopithecus, 



Cercocebus, Cynocephalus (Primates). 

 Indris, Lemur, Galago, Chirogaleus, Hapalemur, 



Lepilemur, Perodicticus, Arctocebus, Micro- 



cebus (Lemurs). 

 Epomophorus, Hypsignathus, Macronycteris 



(Bats). 

 Petrodromus, Rhynchocyon, Centetes, Hemicen- 



tetes, Ericulus, Oryzoryctes, Echinops (Insecti- 



vora). 

 Helogale, Bdeogale, Eupleres, Cynictis, Lycaon, 



Megalotis, Ictonyx, &c. (Carnivora). 




CH. Il] PECULIAR AFRICAN ANIMALS. 99 



Potamochoerus, Phacochcerus, Oreas, Kobus, Al- 



cephalus, &c. (Ungulata). 



Lasiomys, Lophiomys, Saccostomus, Pedetes, Ano- 

 malurus, Aulacodus, Pectinator, Bathyerges, 

 Georychus, &c. (Rodents). 



Parisoma, Artamia, Hypocolius, Corvultur, Hy- 

 phantornis, Vidua, Buphaga, Crithagra, Ama- 

 dina, &c. (Passeres). 



Dendropicus, Geocolaptes, Pogonorhynchus, Buc- 

 canodon, Xylobucco, Coua, Atelomis, Ispidina, 

 Bucorvus, ToccuSy &c. (Picarians). 

 Alectrcenas, (Ena, Chalcopelia, &c. (Columbidse). 

 Agelastes, Numida, Ptilopachus, &c. (Gallina- 



cese). 

 Polyb oroides, Lophoaetus, Melieirax, Nisoides, &c. 



(Accipitres). 



Me&ites, Himantornis (Rallidae). 

 Scopus, Balceniceps (Ardeidse). 



The lion, panther, elephant, and rhinoceros are also of 

 course among the most characteristic African Mammalia. 

 Of Rhinoceroses there are apparently three species, of 

 which only two, R. simus and R. bicornis, are at all known. 

 The third has been lately reported. Also limited to this 

 region are the zebras and quaggas, the last practically, 

 if not actually, extinct. Of chimpanzees there are two 

 well-marked species, the " common " chimpanzee and 

 Anthropopithecus calvus, a species discovered by du 

 Chaillu and until lately represented by a living specimen 

 ("Sally") at the Zoological Society's gardens. It is 

 quite likely that these are not the only two species of 



72 




100 MAMMALS AND BIRDS OF AFRICA. [CH. II 



chimpanzee. The Ethiopian region contains the majority 

 of the antelopes; but in contrast to this abundance of 

 antelopes is the total absence of deer. Another group 

 which might be expected to occur, but which is in- 

 explicably absent, is that of the bears. The hippopotamus 

 is represented by two species, one of which, the small 

 Liberian hippopotamus, has been placed in a distinct 

 genus, Chwropotamus. This proceeding however according 

 to Sir William Flower is unnecessary. The Lemurs, 

 which form so characteristic a part of the fauna of this 

 region, are nearly all of them limited to Madagascar as 

 indeed are many of the peculiar Ethiopian genera. They 

 have been treated of in the more particular account which 

 I give elsewhere (below) of the fauna of Madagascar. One 

 or two resemblances between Africa and the Neotropical 

 region have been noted under the account of the latter. 

 Most of the resemblances of Africa are with the Oriental 

 region. Thus the hornbills and barbets range through 

 both regions, as do the panther and lion. The elephant 

 and rhinoceros are only found in the Oriental region 

 outside of the Ethiopian ; but the species, and even, 

 according to some systematists, the genera are different 

 in the two cases. 



Among birds, the huge whale-bill (Balceniceps) is one of 

 the most remarkable of African types. Its ally, the hammer- 

 head (Scopus), which seems to stand half-way between 

 the Herons and Storks, is a widely-spread African type. 

 The ground hornbill, which is undoubtedly a hornbill, 

 though a very aberrant one, is almost equally singular. 

 The colies and plantain eaters (Coliidse and Musophagidae) 




CH. Il] SUBDIVISIONS OF ETHIOPIAN REGION. 101 



are two groups of uncertain affinities ; as the late Prof. 

 Garrod pointed out, the latter has resemblances to the 

 Gallinacese. Mesites of Madagascar will be found referred 

 to under the description of the fauna of that island. The 

 peculiar types of birds are by no means so numerous or so 

 important as they are in South America. 



The Ethiopian region is divisible into the following 

 sub-regions : (I) East-African, (II) West-African, (III) 

 South-African, (IV) Mascarene. 



East-African sub-region. This sub-region includes 

 not only east but also the greater part of central Africa, 

 and it extends to the north so far as to include Arabia, 

 Abyssinia and the south of Egypt. Below the Sahara it 

 extends right across the continent to the Atlantic, its 

 lower boundary being at about the river Gambia, and 

 again below the West-African sub-region it extends right 

 across. Among the peculiar Mammalia of this sub-region 

 are the Gelada baboon of Abyssinia, the curious little 

 naked and burrowing rodent Heterocephalus and another 

 rodent, Pectinator. The rhinoceroses and the giraffe are 

 practically confined to it, but this restriction is one of the 

 many cases of the limitation of faunas largely due to man. 

 Among birds the boatbill Balceniceps is peculiar, and so is 

 the shrike Hypocolius. But on the whole the sub-region 

 is not well marked by its peculiar types, though abound- 

 ing in the characteristically African forms. 



II. The West-African sub-region extends as far south 

 as the Congo. It is characterised by the Gorilla and by 

 at least one species of Chimpanzee, the Anthropopithecus 

 calvus. The Potto, Perodicticus, and the nearly allied, if 




102 ORIENTAL REGION. [CH. II 



not generically identical, Angwantibo (Arctocebus), are the 

 lemurs which are confined to this sub-region. Potamogale, 

 an Insectivore with the appearance and the habits of an 

 otter, and Hyomoschus complete the list of the more 

 salient mammalian types which are West- African. Among 

 birds perhaps the most remarkable form is a species of 

 Pitta, the only species of this oriental genus which reaches 

 Africa at all. The birds are on the whole not remarkable 

 or distinctive. 



III. The South-African sub-region is bounded to the 

 north entirely by the East- African region, which here as 

 well as to the north of the West- African sub-region 

 extends right across the continent. The sub-region has 

 one family to itself, the Chrysochloridse or Golden moles. 

 The Hysenoid genus Proteles and the Hunting dog Lycaon 

 are peculiar to it. Bathyerges and the jumping hare 

 Pedetes are among the eighteen genera of mammals 

 which are peculiar to South Africa. The birds are not 

 remarkable. 



IV. The Mascarene sub-region is dealt with below. 



IV. The Oriental region. 



To this region Mr Sclater at first gave the name of 

 " Indian " ; but Mr Wallace proposed to replace this name 

 by the more general expression " oriental," a suggestion 

 which has met with Mr Sclater's approval. This region 

 comprises not only the peninsula of India and the more 

 tropical parts of China, but it includes also a large pro- 

 portion of the islands of the eastern archipelago. The 




CH. II] PECULIAR GENERA OF ORIENTAL REGION. 103 



boundary between it and the Australian region has been 

 termed u Wallace's line," and divides the island of Bali 

 from that of Lombok to the south, and the island of 

 Borneo from Celebes on the north. 



(i) Families peculiar to the Oriental region. 



Galeopithecidce, Tupaiidce (Insectivora). 

 Phyllornithidce, EurylcemidcK (Passerines). 



(ii) Genera peculiar to the region. 



Simia, Hylobates, Siamanga, Presbytes (Primates). 



Nycticebus, Loris (Lemurs). 



Megc&rops, Aquias, Phyllotis, &c. (Bats). 



Gymnura (Insectivora). 



Viverricula, Arctogale, Cyon, Arctonyx, Mydaus, 



&c. (Carnivora). 

 Tragulus, Cervulus, Portax, Antilope, Tetracwos 



(Ungulates). 

 Platacanthomys, Spalacomys, Phloeomys, Pteromys, 



Acanthion (Rodents). 

 Garrulax, Timalia, Mixornis, Paradoxornis, Eni- 



curus, Salpornis, Dendrophila, Sylviparus, Cissa, 



Urocissa, Dendrocitta, &c. (Passeres). 

 Chrysocolaptes, Megalcema, Phcenicophaes, Carpo- 



coccyx, Nyctiornis, Harpactes, Buceros, Aceros, 



Rhinoplax, &c. (Picarians). 

 Pavo, Polyplectron, Euplocamus, Gcdloperdix (Gal- 



linaceae). 



Hierax, Ketupa, Photodilus (Accipitres). 

 Hydrophasianus (Rallidse). 

 Among the most characteristic animals of this region 




104 ORANG AND GIBBON. [CH. II 



stands in the first place the Orang, of which there may or 

 may not be more than a single species. The Anthropoid 

 apes are also represented by the agile family of the Gibbons 

 (Siamanga and Hylobates). The two genera of Apes, 

 Macacus and Cynopithecus, might really for all practical 

 purposes have been included among the list of peculiar 

 genera, for they only just get outside the region. Among 

 carnivorous animals the Tiger is one of the most noticeable, 

 though it is not strictly confined to the region, getting 

 north into even the colder parts of the Palsearctic region. 

 The remarkable lemur Tarsius, which is generally made 

 the type and only member of a special family of the 

 Lemurs, only just ranges beyond the Oriental region, 

 while the " Slow Loris " and an ally represent the more 

 normal lemurs. The Ungulates are many and character- 

 istic. In addition to the peculiar genera mentioned in the 

 above list there is of course the Indian elephant and the 

 Malayan Tapir; three out of the five existing species of 

 rhinoceros are also natives of this region. The others, as 

 has been already mentioned, are Ethiopian : the porcupine 

 Atherura is a genus which is common to this region and 

 to the Ethiopian. So too the Manis or Scaly anteater. 

 The flying squirrels, Pteromys, get as far north as Japan, 

 but there are some who would place at least the southern 

 portion of this empire in the Oriental rather than in the 

 Palsearctic region. Of birds the family TimeliidaB, the 

 " Babbling thrushes," are very nearly absolutely confined 

 to this region ; in Mr Wallace's list 21 out of a total of 27 



O ' 



genera, which he allows to the family, are exclusively 

 Oriental. Some of the most magnificent species of the 




CH. Il] ORIENTAL SUB-REGIONS. 105 



pheasant tribe are entirely or mainly restricted to this 

 region and are among the most characteristic of the bird 

 inhabitants. The Cuckoos are well developed, and are 

 represented by 18 genera, of which 2 are peculiar to the 

 region ; but here, as in so many cases, the limits of the 

 genera are somewhat uncertain. The Bee-eater Nyctiornis 

 is an oriental genus, and oriental only. The parrots are 

 abundant, but there is only a single peculiar genus, 

 Psittinus. The rest are mainly of Australian types, but 

 the genus Palceornis is in addition African. The remark- 

 able owl Photodilus has perhaps a near ally in Heliodilus 

 of Madagascar, both of these genera, especially the latter, 

 are again allied to Strix and form with it a special sub- 

 family of the Owls. Another highly characteristic genus 

 of birds is the Surgeon bird, Hydrophasianus, which has 

 an ally in the genus Parra in the New World. The 

 Ralline birds are however not abundant or represented by 

 many peculiar types in the Oriental region. 



The Oriental region has also four sub-regions, (I) 

 Indian, (II) Ceylonese, (III) Indo-Chinese, (IV) Malayan. 



I. Indian sub-region. This sub-region comprises the 

 entire peninsula of Hindostan. It does not abound in 

 peculiar forms, but there are a few which are confined to 

 it. The genus Tceniogale among the Viverridse is in this 

 position ; the majority of the oriental Antelopes have 

 here their head- quarters. 



II. The Ceylonese sub-region includes besides the island 

 of Ceylon a large part of southern India. It is a little 

 richer in peculiar types, but is still not very peculiar. 

 The lemur Loris is found here ; the rodent genus Plata- 




106 FAUNA OF CELEBES. [CH. II 



canthomys is another peculiar type. Several species of 

 " Holy ape " (Semnopithecus) are limited to this sub-region. 

 As to the birds Mr Holdsworth allowed in 1872, 325 

 species, of which 37 are peculiar to Ceylon. This number 

 is raised by Mr Wallace to 80 for the whole sub-region. 

 There is only one genus that is peculiar, viz. Elaphromis 

 and a sub-genus Stumbmis. 



III. The Indo-Chinese sub-region includes the Hima- 

 layas as well as Siam and tropical China. Among peculiar 

 genera of Mammals are the Viverrines Urva and Arctonyx, 

 and the remarkable carnivore JSlurus 1 . There are a 

 number of peculiar birds of the passerine and picarian 

 groups ; these include the genera Liothrix, Urocissa, Aceros 

 (a hornbill), and a number of others ; the Gallinaceous 

 Ceriornis (the Tragopan) is another genus nearly limited 

 to the sub-region. 



IV. The Malayan sub-region, as might be inferred 

 from the fact that it is almost entirely made up of islands, 

 has a number of peculiar forms. The Anthropoid apes of 

 the east are most abundant here, and the Orang is found 

 nowhere else : the lemur Tarsius is very nearly confined 

 to this sub-region, not occurring in any of the other sub- 

 regions but just passing the boundary of the Australian 

 region. The insectivore Gyrnnura,, the curious mountain 

 living carnivore Mydaus, the Indian Tapir are among 

 other mammals that are confined to this sub-region. If 

 we regard the island of Celebes 2 , that " fragment of 

 miocene Asia," as a part of this region a position to 



1 This is also palasarctic. 



2 Mr Sclater does in his most recently expressed opinion, Ibis, Oct. 1891. 




CH. II] NEOTROPICAL REGION. 107 



which Mr Wallace does not commit himself it is a tower 

 of strength in the way of peculiar forms. There are here 

 the Babirussa, the Bull -antelope (Anoa) and the ape 

 genus or sub-genus Cynopithecus. Among birds this sub- 

 region has as peculiar to it the genus Timelia among the 

 " Babbling thrushes," Eupetes, a curious form which Mi- 

 Forbes placed in the Timeliidse, arid quite a number of 

 other Passerine genera. The Australian Megapodius gets 

 into this sub-region, and there is the cuckoo Garpococcyx. 



V. The Neotropical region. 



This region has obvious boundaries for the greater 

 part of its extent, since it consists of the continent of 

 South America. It also includes the West Indies and 

 the greater part of Central America. 



(i) Families peculiar to the Neotropical region. 



Cebidce, Hapalidce (Quadrumana). 



Chinchillidce, Caviidce (Rodents). 



Bradypodidce, Dasypodidce, Myrmecophagidce (Eden- 

 tates). 



Ccerebidce, Oxyrhamphidce, Pipridce, Cotingidce, Phy- 

 totomidce, Dendrocolaptidce, Formicariidce, Ptero- 

 ptochidce (Passeres). 



Rhymphastidce, Bucconidce, Galbulidcv, Todidcv, Mo- 

 motidce, Steatornithidcv (Picarians). 



Cracidce, Tinamidce (Gallinaceye). 



Opisthocomidce (" Hoatzin "). 



Thinocoridce, Cariamidce, Aramidce, Psophiidce, 

 Eurypygidce, Palamedeidce ("Grallse"). 




108 BIRDS OF S. AMERICA. [CH. II 



(ii) Genera peculiar to the region. 







Pteronotus, Chilonycteris, Noctilio (Bats). 



Solenodon (Insectivore). 



Icticyon, Galictis, Nasua, Cercoleptes (Carnivora). 



Dicotyles, Lama (Ungulates). 



Neotomys, Cercokibes, Chcetomys (Rodents). 



Chironectes, Hyracodon (Marsupials). 



Mimocychla, Donacobius, Cyanocorax, Basileuterus, 



Sy calis, Diuca, &c. &c. (Passeres). 

 Picumnus, Chloronerpes, Guira, Neomorphus, Pany- 



ptila, &c. &c. (Picarise). 

 Ara, Caica, Chrysotis, Pionus, &c. (Psittaci). 

 Columbula, Zenaida, Starncenas, &c. (ColumbaB). 

 Odontophorus, Dendrortyx, Eupsychortyx (Galli- 



nacese). 

 Sarcorhamphus, Spiziastur, Morphnus, &c. (Acci- 



pitres). 



Heliornis, Oreophilus, Pluvianellus, &c. (Rails). 

 Tigrisoma, Cancroma (Ardeidae). 

 Micropterus, Merganetta (Anatidas). 

 Rhea (Struthiones). 



X 



Besides the peculiar families enumerated above the 

 Nearctic region shares with the present the exclusive 

 possession of the Humming-birds (Trochilidae), Tanagers, 

 Mrdotilitidse, Vireonidae, Tyrannidse, Conuridse, of all of 

 which the bulk of the species are South American. The 

 American vultures, which have been aptly termed by Mr 

 Seebohm Mimogypes, are chiefly neotropical, but also 

 range into the northern hemisphere. Of characteristic 




CH. Il] PECULIAR TYPES OF ANIMALS. 109 



forms not by any means either as to the family or the 

 genus to which they belong, which are confined to this 

 region, extending sometimes for a greater or less distance 

 into the Nearctic, are the Tapirs, which are represented 

 by several species, some of which were separated by the late 

 Mr Alston as a distinct genus Elasmognathus : the Jaguar 

 and the Puma among the Carnivora, the former being 

 confined to the region : the Opossums of the genus 

 Didelphys are found here and in the southern parts of 

 the Nearctic : the Skunk may be mentioned in the same 

 category as the last : Bassaris is a carnivorous animal 

 whose affinities, now known to be with the bear tribe, 

 were at one time unrecognised ; it also extends into the 

 warmer parts of North America. The number of peculiar 

 genera belonging to the region is very large. Four of the 

 peculiar Gralline families contain but a single genus 

 apiece and very few species between them ; they are all 

 of them birds whose position in the system is much 

 disputed, owing no doubt to their being the impoverished 

 relics of groups of birds at one time more abundant. 

 Palamedea and Chauna are believed to be a relic of an 

 ancestral tribe of anatiform birds ; Cariama is said by 

 some to present resemblances to the Secretary bird of 

 Africa and to have therefore some relations to the birds 

 of prey. Psophia and Aramus are more distinctly rails, 

 while Eurypyga again is a bird which is allied to the 

 New Caledonian Rhinochetus, and to the Madagascar 

 Mesites, and possibly represents the sole remaining Ame- 

 rican type of a nearly extinct order of birds once 

 universally distributed. Of Opisthocomus the same kind 




110 TINAMOUS AND CURASSOWS. [CH. II 



of remarks can in all probability be safely made. It 

 seems to be an outlier of the Gallinaceous tribe, which is 

 itself represented in this region by two other ancient 

 families (see p. 28), the Tinamidae and the Cracidse, of 

 which of course the Tinamidae are the most ancient, 

 inasmuch as they alone of all Carinate birds resemble the 

 Ostrich tribe in the absence of any fusion between the 

 pubes and the ischia. The Oil-bird (Steatornis) cannot 

 perhaps lay claim to any great antiquity but it is a very 

 remarkable type of Caprimulgine bird. The Trogons and 

 Barbets are also found in the Ethiopian and Oriental 

 regions. The scarlet Ibis, and the Boatbill Cancroma a 

 Night Heron with an enlarged beak, approaching that of 

 the African Balceniceps are other instances of peculiar 

 South-American birds. 



The Neotropical region is divisible into four sub- 

 regions ; these are (I) Chilian, (II) Brazilian, (III) 

 Mexican, (IV) West-Indian. 



I. The Chilian sub-region. This includes the whole 

 of Patagonia and the greater part of Chili ; the Andes 

 divide it to the north from the Brazilian sub-region. It is 

 well marked by several groups of animals, which give it 

 a perfectly distinctive character. In the first place we 

 have the rodent family of the Chinchillidae ; the Llama, 

 Huanaco, Alpaca and Vicuna belonging to the genus Lama, 

 are as characteristic ; two genera of Armadillos, Tolypeutes 

 and Chlamydophorus, are restricted in their range to this 

 region, and it has other peculiar rodents in addition to 

 the family mentioned. Among birds the family Thino- 

 coridas with the two genera Thinocoris and Attagis, which 




CH. Il] TAPIRS AND EDENTATES. Ill 



the late Prof. Garrod showed to be most nearly related to 

 the " Courser " of the old world, is one of the most typical 

 of the sub-region. The Tinamou genus Calodromas, with 

 ca3ca unique in their complicated branching, is also 

 confined to the sub-region. Ehea is equally limited to 

 this part of the world, and there are numerous other 

 genera of birds belonging to many families, which exist 

 only in the Chilian sub -region. Among earthworms it 

 contains all or nearly all of the genera Acanthodrilus and 

 Microscolex ; this group of animals offering one of the 

 best reasons for its separation. 



II. The Brazilian sub-region. This sub-region includes 

 all the forest region of South America and is practically 

 coextensive with the political division of the continent 

 known as Brazil. It reaches up to the sea on the north 

 and across the Andes on the west. The monkeys, Lago- 

 thrix, Brachyurus and Pithecia, are limited to this region, 

 which indeed contains nearly all of the arboreal animals of 

 South America. The Tapirs of the genus Tapirus are 

 found here only. The Great Anteater (Myrmecophaga), 

 the Sloth Bradypus and a few Armadillos are confined to 

 the sub-region. Among birds it has the isolated genera 

 Psophia and Eurypyga, besides innumerable genera be- 

 longing to the Cotingidas and other families. 



III. The Mexican sub-region. This sub-region is in 

 some respects intermediate between the rest of the Neo- 

 tropical and the Nearctic regions. It is not so rich in 

 peculiar types of South American animals as are either of 

 the sub-regions already described. There are however not 

 a few types entirely restricted to tropical Mexico. Among 




112 WEST INDIES. [CH. II 



the most important of these is the mountain Tapir 

 Elasmognathus ; the Bassaris, a raccoon-like animal for- 

 merly and wrongly assigned to the Viverridse, is Nearctic 

 as well as central American. The only other genus of 

 Mammalia which is really confined to the sub-region 

 besides the Tapir is a genus of mice, Myxomys. As with 

 the Mammalia so with the birds this sub-region is the 

 common meeting ground of the Nearctic and Neotropical 

 fauna, with a distinct bent towards the latter. Mr 

 Wallace states that there are in all 37 genera of land 

 birds confined to it, all of which are of common Nearctic 

 or Neotropical families. 



IV. The West-Indian sub-region. This sub-region 

 consists of the islands of the West Indies, and bears a 

 somewhat analogous relation to the continent of South 

 America that the island of Madagascar does to that of 

 Africa. As far as concerns Mammals it is largely marked 

 by negative characters ; there are no Edentates, monkeys 

 or Carnivora ; but the two older (?) groups of mammals, 

 Rodents and Insectivora, are represented by peculiar types. 

 The latter is represented by the genus Solenodon, which 

 belongs to the family Centetidse, elsewhere only found in 

 Madagascar. The Rodent Capromys is the most peculiar 

 representative of its order. The birds are also remarkable ; 

 the genus Todus, which the late Mr Forbes elevated to a 

 group equivalent to the rest of the Picarian birds, is 

 found here and here only. It is widely spread in the 

 islands and has peculiar forms in many of them. The 

 other birds are not so remarkable ; they are characteris- 

 tically neotropical, belonging to such families as Trochilidse 




CH. u] " WALLACE'S LINE." 113 



(Humming birds), Cotingidse (Chatterers), Coerebidse 

 (Sugar birds). 



VI. The Australian region. 



* 



The Australian region consists, as its name denotes, of 

 the Australian island-continent ; it also embraces the 

 island of New Zealand to the east and various small 

 scattered islands in the neighbourhood of this. The 

 islands of the Pacific lying to the north and to the east of 

 Australia also are referable to the same region, as are the 

 great islands of New Guinea, and probably Celebes. The 

 chain of East Indies beginning with Java is partly 

 Oriental and partly Australian ; the division between the 

 two often spoken of as " Wallace's line " lies between the 

 islands of Bali and Lombok. 



One order, the Monotremata, is peculiar to this region. 



Families peculiar to the Australian region. 



Dasyuridce, Mynnecobiidce, Pemmelidce, Macropo- 



didce, Ph alangistidce, Ph ascolomyidcu (Marsupials). 

 Paradiseidce, Meliphagidce, Drepanididcv, Menuridce, 



Atrichiidce (Passeres). 

 Platycercidcv, Trichoglossidce, Nestoridce, Stringopidce 



(Parrots). 



Didunculidw (Pigeons). 

 Rhinochetidw (Grallas). 

 Casuariidce, Apterygiidce (Struthiones). 



Oenera peculiar to the region. 



Ht/poderma, Notopteris, Mystacina (Bats). 

 Bctbyrussa (Pigs). 

 Anoa (Bovidae). 



B. Z. o 




114 AUSTRALIAN BIRDS. [CH. II 



Pseudomys, Hapalotis, Hydromys, Acanthomys, 



Echiothrix (Rodents). 

 Malurus, Calamanth/us, Orthonyx, Artamides, Pachy- 



cephala, &c. (Passeres). 

 Scythrops, Rhamphococcyx (Cuckoos). 

 Dacelo, Tanysiptera, Podargus, Aegotheles, &c. 



(Picarians). 

 Calopsitta, Microglossus, Eos, Eclectics, Trichoglossus, 



&c. (Parrots). 

 Turaccena, Calwnas, Otidiphaps, Phaps, Geophaps, 



&c. (Pigeons). 



Talegallus, Megacephalon, Lipoa (Megapodes). 

 Urospiza, Uroaetus, Harpa, Hieracidea, &c. ( Accipi- 



tres). 

 Ocydromus, Tribonyx, Habroptila, Pareudiastes 



(Rallidse). 

 Thinornis, Pedionomus, Anarhynchus. Erythrogonys 



(Charadriidse). 

 Malacorhynchus, Hymenolcemus, Biziura, Cereopsis 



(Anatidae) 1 . 



The family of the Megapodes is as nearly as possible 

 confined to this region, a single species getting as far as the 

 Andamans in the Oriental region ; so too the Cacatuidse 

 which extend beyond it only to the Philippines. Of 

 course the most impressive character of the region is the 

 possession of nearly all the Marsupials ; with the excep- 

 tion of a single family, the Didelphida?, found in North, 



1 The above list contains the peculiar Celebes genera. The relations 

 of this island are extremely doubtful. 




CH. Il] PARROTS AND PIGEONS. 115 



Central and South America, there are no Marsupials found 

 outside of Australia and the Australian region. As this 

 region consists so largely of islands it might be expected 

 that the peculiar forms have often an extremely limited 

 range within it ; that is the case, and I have dealt 

 elsewhere with the fauna of New Zealand, which is an 

 important part of the Australian region, so important 

 indeed that it has been proposed to separate it off as an 

 equivalent region. Among the characteristic animals of 

 Australia that do not belong to genera or families limited 

 to the region is the wild dog, the Dingo ; it has been 

 doubted whether this is really an indigenous animal at 

 all. 



It is often suggested, or perhaps left to be inferred, 

 that the Avifauna of this region is inferior in its distinc- 

 tiveness to the Mammalian ; no doubt the absolutely 

 unrivalled peculiarity of that fauna tends to obscure by 

 contrast the real and numerous peculiarities of the bird 

 fauna ; but a glance at the above list will show that 

 Australia and its adjacent islands in reality abounds with 

 peculiar types of birds. It is specially noteworthy on 

 account of the great abundance and variety of the Parrots, 

 being comparable to indeed really excelling in this 

 respect South America. Highly characteristic also of 

 the region are the Pigeons. These rather defenceless 

 birds, which have no beak or claw to speak of, and which 

 construct rude and easily accessible nests exposed to view 

 in the most open manner, possibly owe their abundance 

 to the absence of a great variety of Carnivorous Mam- 

 malia. They are also to a considerable extent marked 



82 




116 AUSTRALIAN SUB-REGIONS. [CH. II 



with green, a protective colour in the forests which they 

 inhabit. Mr Wallace, to whom the above suggestions in 

 explanation of the great prevalence of Pigeons are due, 

 estimates that " three-fourths of the genera have repre- 

 sentatives in the Australian region, while two-fifths of 

 the whole are confined to it." 



The Australian region is not quite so destitute of 

 Mammals not belonging to the orders Monotremata and 

 Marsupialia as is sometimes apt to be inferred. Apart 

 from the peculiar genera of Rodents and the few other 

 peculiar forms enumerated in the above table, a Macaque 

 and a Cynopithecus get into the region where it touches 

 the Oriental ; the remarkable Oriental Lemur the Tarsius 

 also enters the region ; Viverridse and shrews are not 

 unknown, though few and rare ; the genus Sus extends as 

 far into the region as New Guinea. On the whole this 

 is perhaps the most isolated in its affinities of all the 

 regions. The boundary between it and the Oriental is 

 sharply marked ; I have dealt elsewhere (see below) with 

 such resemblances as it affords to other parts of the world 

 and the Neotropical region. 



The Australian has four well marked sub-regions, viz., 

 (I) Austro-Malayan, (II) Polynesian, (III) Australian, and 

 (IV) Novo-Zealanian. 



I. The Papuan or Austro-Malayan sub-region in- 

 cludes not only New Guinea and all the islands lying to 

 the west of it as far as the commencement of the Oriental 

 region, but the extreme north of the continent of Aus- 

 tralia. Being entirely, or nearly entirely, made up of 

 islands it has a large number of peculiar forms. The 




CH. II] MARSUPIALS. 117 



Marsupials get to thin out here considerably; but there 

 are peculiar genera ; in New Guinea itself we have 

 Dorcopsis ; the Tree Kangaroo Dendrolagus is confined to 

 New Guinea and North Queensland ; a genus of Pha- 

 langers Distcechurus is also peculiar, and there are several 

 species characteristic of these islands ; the recently dis- 

 covered Echidna, Proechidna bruijnii, is peculiar to New 

 Guinea. Among birds the most characteristic are the 

 Birds of Paradise belonging to the genera Paradisea, 

 Manucodia, Seleucides and many others. The cockatoo 

 Microglossus is a peculiar genus and the Cassowaries have 

 here their headquarters. 



II. Polynesian. This sub-region is largely dealt 

 with below ; it is characterised rather by the absence of 

 forms which ought, so to speak, to be there than by the 

 presence of peculiar forms. 



III. The Australian sub-region is of course the head- 

 quarters of the Marsupials and Monotremes, of which 

 latter group the Platypus is restricted to the sub-region. 

 Among Marsupials the Wombats, Thylacine and Koala 

 are confined to it. Another remarkable type of Marsupial 

 entirely confined to this sub-region is the small insect- 

 eating Myrmecobius ; the lately discovered " Marsupial 

 mole" is another type which marks out this from the 

 other sub-regions. This sub-region has according to Mr 

 Wallace a larger proportion of peculiar birds than any 

 other sub-region of any region. Nineteen-twentieths of 

 the birds are confined to it. The Emeu and the Cereopsis 

 goose are among the most characteristic forms. 




118 COLOUR AND DISTRIBUTION. [CH. II 



IV. The Novo-Zealanian sub-region comprising New 

 Zealand and some of the adjacent islands is described 

 in detail below. 



Some graphic Methods of presenting the facts 



of Distribution. 



In order to get a clear idea of the facts of Zoogeography 

 and to compare one series of facts with another it is 

 requisite to present them in a graphic fashion. The usual 

 method is to indicate the different Distributional regions 

 upon a map by the help of varied colour. The colour 

 might even be made to some extent appropriate ; the 

 Neotropical region Dendrogsea as Mr Sclater terms it 

 preeminently a region of forests and inhabited by so many 

 arboreal types, might be conveniently coloured green ; 

 those who accept the Holarctic realm of Prof. Newton 

 might suitably leave it white in order to suggest the 

 characteristic Arctic forms. Prof. Camerano has recently 

 attempted to show that there is a distinct relation between 

 colour and geographical range. He thinks that yellow is 

 the prevailing colour in Africa, grey in Asia and so forth. 

 This method of colouring the primary regions may com- 

 mend itself to some. A difficulty is offered by the 

 transitional tracts which combine the characters of the 

 two regions between which they lie. These transitional 

 areas are perhaps more marked between the Palaearctic 

 and the Ethiopian on the one hand and between the 

 Palsearctic and Oriental on the other. Prof. Mobius 1 

 colours these transitional areas with a paler hue of the 



1 Die Tiergebiete derErde &c. Archiv f. Naturg. 1891, p. 277. 




CH. II] 



DIAGRAMS OF DISTRIBUTION. 



119 



tint applied to the region which they most resemble. 

 Dr Heilprin prefers to shade the transitional areas. This 

 method however is too voluminous and expensive to be 

 used in illustration of the geographical range of different 

 species, genera and families. The number of maps re- 

 quired is reduced by a plan adopted by Dr Greve 1 in a 

 series of papers upon the distribution of the different 

 groups of Carnivora. The areas of certain species that do 

 not overlap are coloured with different tints ; where there 

 is an overlapping the boundaries are indicated by differ- 

 ently coloured lines made up of dots or strokes or crosses 

 &c., &c. The complexity of the result thus produced 

 seems however to counterbalance the economy of space. 

 There is no doubt that maps convey a more rapid and 

 accurate impression than tables ; and Mr J. A. Allen has 

 eliminated the element of expense by suggesting diagram- 

 matic maps which can be constructed of lines and dashes 

 in ordinary use by printers. The following scheme 



Nearctic 



Neotropical 



Palasarctic 



Ethiopian 



a 



Oriental 



Australian 

 d 



Zoologisclie Jahrb. Abt. f. Syst. Bd. vi. 1892. 




120 



REPTILES AND 



[CH. II 



slightly altered from the original, indicates the regions 

 of Sclater and Wallace with the principal sub-regions, 

 i.e. (a) Madagascar, (b) Malaya, (c) Patagonia, (d) New 

 Zealand. 



The wavy lines connecting certain of the regions show 

 that they are related. This method (which I have 

 already utilised) is useful for indicating the range of 

 species, genera or families, the names of which can be 

 written in the spaces ; but it is more particularly 

 advantageous for a broad survey of the divisions of 

 the earth's surface which a study of different groups 

 necessitates and which may be compared. The following- 

 are Trouessart's schemes of herpetological and mammalian 

 regions. 



REPTILES 



Nearctic 



Neotropical 



Palaearetic 



Oriental 



Ethiopian 



Australian 




CH. II] 



MAMMALS. 

 MAMMALS 



Arctic 



121 



Holarctic 



Neotropical 



Antarctic 



Australian 



d 



Mr Mitchell has recently 1 devised a still further sim- 

 plification which again can be printed from ordinary type 

 lines. The regions may be thus indicated. 



Nearctic 



Palaearctic 



Neotropical 



Ethiopian 



Oriental 



Australian 



The scheme may be made more complete by the 



1 P.Z.S. 1890, p. 607. 




122 



MR MITCHELLS SCHEME. 



[CH. II 



addition of the sub-regions. As Mr Mitchell points out 

 the four sub-regions of each region except in the case of 

 the Nearctic lie in a general way two to the north and 

 two to the south. The sub-regions may be indicated by 

 the following numbers. 



Palcearctic region. 

 N. European 1 

 Mediterranean 



2 



Siberian 3 



Manchurian 4 

 Oriental region. 

 Hiiidostan 1 

 Ceylon 2 



Indo-Chiiia 3 

 Indo-Malay 4 

 Nearctic region. 

 Canada 1 



California 2 



Rockies 3 



E. States 4 



Ethiopian region. 

 W. African 1 

 S. African 2 

 E. African 3 

 Madagascar 4 



Australian region. 

 Austro-Malay 1 

 Australia 2 



Polynesia 3 



New Zealand 4 



Neotropical region. 

 Mexico 1 



Chili 2 



Antilles 3 



Brazil 4 



The complete scheme therefore will be as follows with 

 the sub-regions shown. 




CH. II] 



DIAGRAM OF RANGE OF LEMURS. 



123 



The range of any particular form is given by leaving 

 out all but the sub-regions where it occurs, putting these 

 in their proper place. Thus the range of the existing 

 Lemurs would be expressed in the following way. 



1 3 



2 



1 3 



4 



It might be advantageous to mark in heavy type those 

 sub-regions which are especially inhabited by the animal 

 in question, and various other modifications are of course 

 possible and will suggest themselves. The great advan- 

 tage of Mr Mitchell's scheme is that it can be so easily 

 used for the purposes of blackboard demonstration in 

 lectures. 




CHAPTER III. 



THE CAUSES WHICH INFLUENCE THE DISTRIBUTION 



OF ANIMALS. 







Distribution not dependent upon temperature. 



IT was at one time held that distribution depended 

 upon temperature ; that therefore the world could be 

 divided into zones corresponding to the belts of varying 

 temperature. 



That the range of animals is to a large degree depen- 

 dent upon temperature is an undoubted fact; and to a 

 certain extent that fact does permit of the zonal arrange- 

 ment of the earth. Only however as concerns the arctic 

 regions ; here we have occasionally the same species 

 ranging right round the pole as we have in the case of 

 the marine mammalia and the birds of the south pole. 

 Some even go so far as to unite for the same reason the 

 Palaearctic and Nearctic regions. On a priori grounds 

 too there would seem to be something to be said for a 

 series of circumpolar regions ; as the earth cooled life 

 would be able to advance from the poles towards the 

 equator, and the whole matter has recently been resusci- 

 tated in the polar theory of the origin of faunas (see 

 below). 




CH. Ill] RANGE OF ARCTURUS. 125 



Distribution of Crustacean Arcturus as illustrative 

 of connection between range and temperature. 



It is chiefly marine organisms which show a close 

 interdependence of temperature and distribution. The 

 Isopod genus Arcturus and the nearly related Astacilla 

 prevail chiefly in the antarctic hemisphere ; it is only 

 recently however that they have been obtained from that 

 part of the world. Until the voyages of the German ship 

 " Gazelle " and the English vessel " Challenger " the two 

 genera were only known from the northern hemisphere. 

 Four or five species of Astacilla occur on the coasts of 

 Great Britain, X. America and Northern Europe ; while 

 the large Arcturus baffini is the only representative of its 

 genus from the north, which is an inhabitant of shallow 

 seas. It is in the antarctic region of the globe that 

 Arcturus is so prevalent. Two species named Arcturus 

 coppingeri and A. ainericanus occur in the shallow water 

 off the coasts of Patagonia ; three species of Arcturus, viz. 

 A. furcatus, A. studeri, A. stebbingi, are met with on the 

 shores of Kerguelen, besides a peculiar genus still refer- 

 able to the same family and containing one species 

 Arcturides cornutus. A single Astacilla, A. marionensis 

 lives, as its specific name implies, on the shores of Marion 

 Island, not so far from Kerguelen ; finally there is a 

 peculiar form with eyes on long but immobile stalks, 

 Arcturus oculatus, on the shores of South Australia. In 

 addition to these inhabitants of shallow water there 

 are a number of species which are only found in deep 

 water and one (Arcturus furcatus) which lives in both 




126 SHALLOW WATER AND DEEP SEA ARCTURUS. [CH. Ill 



shallow and deep water a very rare exception so far as 

 this group is concerned. The purely deep sea forms with 

 their habitats are the following : 



A. glacialis, Antarctic. 



A. spinosus, Antarctic. 



A. anna, Antarctic. 



A. brunneus, Antarctic. 



A. my ops, Antarctic. 



A. cornutus, Indian Archipelago. 



A. spinifrons, Fiji. 



A. purpureus, West Indies. 



A. abyssicola, Society Islands and Cape York. 



A. t uber osus, Arctic. 



A. hystrix, Arctic. 



The facts at our disposal about the distribution of this 

 family appear to indicate that the genus Arcturus is 

 typically a deep sea genus ; there are twelve deep sea 

 species as against seven shallow water forms, one being 

 common to both coasts and sea of great depth. The 

 shallow water forms are with one exception exclusively 

 antarctic in range ; while in the closely allied genus 

 Astacilla the converse is the case, there being but one 

 antarctic species. The facts look very much as if range 

 here were more a question of temperature than anything 

 else ; the intervening hotter parts of the oceans are 

 without Arcturi ; but the southern forms have been able 

 to reach the northern hemisphere or vice versa by taking 

 a long dive and coming up again above the equator. The 

 deep sea in fact is a cool pathway along which Crustaceans 




CH. Ill] FLORA OF NEW ZEALAND. 127 



unable to withstand the higher temperature of the surface 

 waters in the tropics can pass in safety. 



This view however mav be too elaborate ; besides it 



mf 



should apply also to the Serolidse which are considered 

 below 1 ; another suggestion may arise from the habits 

 of these Crustaceans ; the Serolidse live at the bottom and 

 swim and crawl on the sand ; the Arcturidae on the other 

 hand are stated to cling with their hinder thoracic limbs 

 to any available object ; in this way they might easily 

 happen to select some floating piece of wood which would 

 ultimately take them on a voyage to the more northern 

 from the more southern regions. 



An analogous series of facts with perhaps an analogous 

 explanation is offered by the flora of New Zealand. There 

 are many resemblances in the flora of New Zealand to 

 that of Europe. Mr Wallace says that " one-third of the 

 entire number of New Zealand genera (115) are found 

 also in Europe, and even fifty-eight species are identical 

 in these remote parts of the world." No doubt it is easier 

 for many plants than for many animals to cross wide 

 tracts of ocean, but Mr Wallace is of opinion that mountain 

 ranges offer a convenient mode of transit which has been 

 probably made use of. The difficulties of a change of 

 temperature would be in this way overcome ; as a matter 

 of fact European plants are known from intermediately 

 lying mountain tracts such as the Himalayas. 



1 In the Chapter dealing with the Antarctic continent. 




128 SPARROW IN UNITED STATES. [CH. Ill 



The country inhabited by an animal is not neces- 

 sarily the only one in which it can flourish. 



The view that animals are suited to the countries 

 which they inhabit and to no others, that in fact their 

 distribution is a matter of temperature, is proved to be 

 quite untenable by the phenomena of colonisation. Sir 

 Charles Lyell 1 refers to the case of the Ligurian bee, Apis 

 mellifica, which is a native of Europe. It was however 

 introduced by the early settlers into America and has 

 since that time prospered exceedingly on its own account, 

 apart altogether from the protection afforded by man to 

 his own hives. It inhabits the forests of the interior and 

 builds its combs in hollow trees. 



The most striking instance however of successful in- 

 vasion of a new country by foreign colonists is offered by 

 the sparrow. This bird is now as ubiquitous in most 

 parts of the United States as it is in this country. To 

 such an extent has it proved capable of adapting itself to 

 a new soil and somewhat different climate that measures 

 concerted for its destruction by the United States Govern- 

 ment have proved quite incapable of producing any great 

 effect upon its numbers ; and yet it is only a few years 

 since it was artificially introduced. 



Perhaps the most striking example among plants of 

 the capacity which an introduced organism sometimes 

 possesses of suiting itself to new circumstances is the 

 common canal and pond weed of this country, the Anacharis, 



1 Principles of Geology. 




CH. Ill] INTRODUCED ANIMALS. 129 



which was introduced some years since as a rare and 

 interesting botanical specimen. 



The rabbits in Australia are another example, whose 

 abundance in a country which might appear from the 

 nature of its fauna to be unsuitable to the higher Mam- 

 malia, has so far baffled the attempts of science to lessen 

 their numbers. Within the last few years also a species of 

 Zosterops has naturalised itself in New Zealand, this being 

 a case of colonisation not helped or caused by man. The 

 Bee-fly, Volucella, has also of late taken up its abode in 

 the same country and in other parts of the world. 



In fact plenty of examples might be cited from various 

 groups of the animal kingdom to show that there is by no 

 means always a close and inviolable connection between 

 a given animal and the habitat in which it happens to 

 flourish. 



Similarities in the faunas of distant countries. 



Dr Seitz has lately complained that a perusal of such 

 books as Mr Wallace's work upon distribution give an 

 erroneous impression of the characters of different countries. 

 He read that South America has an infinite number of 

 Cotingidse and Pipridse, both of which families of birds 

 are confined to it ; but during his visit to that continent 

 he only occasionally heard the Cotingidae, the Bell-bird 

 Chasmorhynchus to wit. On the other hand he was 

 struck by the resemblance of tropical Africa to tropical 

 America in the large beetles called by the specific names 

 of "Hercules" and "Goliath." The brightly coloured 

 B. z. 9 




130 FAUNAS OF TROPICAL COUNTRIES. [CH. Ill 



flying moths of the tropics of the old and the new worlds, 

 the Agaristida? and Castniidse, the toucans of America 

 and the hornbills of the East also contribute to giving 

 them a similarity. So too the apes and monkeys ; while 

 the newts of the colder regions distinguish them from the 

 tropics. The humming-birds of America have a superficial 

 likeness to the sunbirds of the old world ; the tapir occurs 

 in tropical America and recurs in tropical Asia. Plenty 

 of other such resemblances might be cited. 



But a closer examination of the facts dispels the ideas 

 of a similarity of the fauna to which they at first give 

 rise. The humming-birds are not nearly related to the 

 sunbirds ; nor are the toucans the nearest allies of the 

 hornbills ; ornithologists think that the latter come next 

 to the hoopoes. The apparent similarity in fact is due 

 to a variety of causes. The deserts of America are 

 tenanted by sandy-coloured reptiles just as are the deserts 

 of Asia and Africa ; but in all cases it is believed that the 

 similar plan of coloration is not due to any affinity but 

 to their similar needs. The African lizard assimilates in 

 colour to the sand in and upon which it lives just as does 

 its American representative. Perhaps, as has been sug- 

 gested by a competent observer of the birds and beasts of 

 India 1 , the huge beak of the hornbill has been produced 

 in order to assist it in wrenching off from the stem the 

 often tough fruits upon which it feeds; the toucan may 

 have got its almost equally large bill by reason of the 

 same need. Forest country is inhabited by animals that 

 are adapted to life among trees, whence superficial simi- 



1 A Naturalist on the Prowl, by " Eha." 




CH. Ill] EVOLUTION AND DISTRIBUTION. 131 



larities. It is a matter for the greatest wonder why the 

 old world monkeys have not got prehensile tails. 



On the other hand the similarity of the faunas of 

 tropical countries even when widely separated have some- 

 times another explanation. The tapirs of America and 

 India are unquestionably allied. They are purely tropical 

 animals and yet separated by a stretch of land which is 

 not tropical. But in earlier periods of the earth's history 

 we know that Europe was favoured with a higher tempe- 

 rature than at present ; we also find the bones of tapirs 

 in Europe at that period ; hence the inference that the 

 tapir has been isolated in its present habitats by the 

 gradual decrease of heat in the northern hemisphere. 



These few examples again show how needful it is for 

 the student of Zoogeography to have a thorough acquaint- 

 ance with the structure of animals ; he must be able to 

 distinguish between merely adaptative resemblances and 

 real structural similarities. 



Problems of Distribution and Evolution. 



It is not necessary now to argue against the doctrine 

 of special creation ; evolution in some form or other is 

 almost universally accepted ; and the facts of distribution, 

 as Darwin himself showed in great detail, are among the 

 most convincing proofs of the untenability of any such 

 belief as special creation. We have for instance remote 

 islands, such as the Azores, which are quite capable of 

 supporting mammalian life, as has been abundantly proved 

 by the flourishing condition of purposely or accidentally 



92 




132 ROMANES ON DISTRIBUTION. [CH. Ill 



introduced mammalia ; and yet these islands are totally 

 without any indigenous mammalian population. Many 

 of the forest regions of Africa and Asia enjoy a climate 

 and temperature like that of the forests of South America, 

 and yet we do not find them tenanted by an identical 

 fauna. A locality which is in every way entirely suitable 

 to the life of a particular animal or plant is by no means 

 necessarily inhabited by that particular organism. This 

 of course is not an argument that is necessarily fatal to 

 the doctrine of creation. But it is at least more intelligible 

 on the theory of evolution. As the late Mr Romanes 

 pointed out 1 we can better understand that the 400 or so 

 species of humming-birds are limited to the warmer parts 

 of America because they came into existence in that 

 continent, and are too feeble in organisation to traverse 

 the intervening seas which separate them from equally 

 suitable countries and localities. There is no explanation 

 except that all these 400 were ultimately derived from 

 some American parent stock ; otherwise why should the 

 400 if betokening so many distinct acts of creation have 

 been all of them placed in the same region of the world ? 

 Moreover we are met with the fact that tropical regions 

 of the old world with abundant flowers are tenanted by 

 birds which in some degree resemble the humming-birds 

 and lead the same sort of life. These again are limited 

 to those regions and are not found in America. On the 

 doctrine of special creation it is hard to understand why 

 there should not have been some admixture. 



On the other hand if we accept the theory of descent 



1 Danvin, before and after. Vol. I., The Darwinian Theory. 




CH. Ill] INDEPENDENT ORIGIN OF ALLIED FORMS. 133 



with modification we are in a better position to grapple 

 with the problems offered by the phenomena of the 

 distribution of animals. Indeed if we hold to the opposite 

 theory there are no problems for discussion. 



But though it is absolutely necessary to believe in 

 some theory of descent and modification in order to 

 explain the facts of distribution, this theory itself presents 

 some difficulties which will be briefly indicated. It is 

 usually held that a given species can only come into 

 existence once ; that the same modification can only 

 appear once and never again. Consequently if we meet 

 with the same species in two separate localities, there 

 must have been some time or other communication of 

 some kind between them ; either the animal in question 

 has been able to traverse the intervening barrier or the 

 barrier at one time did not exist. If the opposite view 

 be maintained, and there are some evolutionists who have 

 maintained it, many of the problems connected with 

 distribution will at once disappear. Probably a middle 

 course is here as in so many cases the safer one to follow. 

 The degree of complication of the changes is in all 

 likelihood a safe guide to follow. It is for example 

 inconceivable, as Prof. Lankester has pointed out, that 

 animals which agree in the possession of that characteristic 

 and complicated organ peculiar to the Mollusca and 

 known as the odontophore should not be all of them 

 genetically related. But on the other hand it is easily 

 conceivable that two birds might independently lose a 

 certain muscle ; the fact therefore that they were both 

 without this particular muscle would not be an infallible 




134 MEANS OF DISPERSAL. [OH. Ill 



guide to their relationship. A species of bird or reptile 

 finding its way to an oceanic island might become darker 

 in colour. After an interval the parent stock might send 

 a colony to another oceanic island where the same modi- 

 fication might well occur, thus exactly reproducing the 

 first variety ; this view is supported by Dr Heilprin in his 

 text-book of geographical distribution, who controverts 

 Darwin's suggestion that the same variety cannot be 

 produced twice, owing to the fact that the parent form 

 which gave rise to the variety will be supplanted by its 

 improved offspring, by reminding the reader of the 

 tenacity of form possessed by certain animals, notably by 

 some of the Brachiopods, which have persisted unchanged 

 for many geological periods. Geology also seems to show 

 that forms do reappear after an interval of total absence ; 

 but this may be merely another instance of the lamentable 

 "imperfection of the geological record." Dr Heilprin 

 thinks that the tapir which occurs in the Oriental region 

 and again in the Neotropical may be really the offspring 

 of two distinct lines from separate tapiroid ancestors ; and 

 that therefore this discontinuity of range does not argue 

 an extinct parent form, which sent off offshoots from one 

 continent to the other. 



Other geological facts have to be considered which 

 will be deferred until the next chapter. 



Means of Dispersion of Animals. 



Animals can extend their range either by active or 

 passive migration. Both kinds of migration are hindered 

 by barriers of various kinds. 




CH. Ill] BARRIERS TO DISPERSAL. 135 



A wide expanse of sea is an effectual barrier to the 

 mammalia and reptilia but not altogether to birds, 

 especially if there be islands which shorten the stretches 

 of ocean to be traversed. Even a comparatively small 

 tract of ocean, in some cases a narrow strait, opposes itself 

 as an insuperable barrier to some forms of life. The 

 Amphibia, for example, cannot suffer the contact of sea 

 water, which is also fatal to their eggs. Earthworms are 

 also killed by sea water. The narrowest strait is therefore 

 as efficient a check to the migrations of these animals as 

 is the widest ocean. High mountain ranges are also 

 hindrances sometimes quite effectual to the extension of 

 range of purely terrestrial animals ; partly perhaps on 

 account of temperature but probably more on account of 

 the physical obstacle. A great expanse of desert is often 

 as effective a barrier as a tract of sea. The desert of 

 Sahara separates two faunas that are widely different. 

 Changes in climate are also to some extent hindrances, 

 though not to so great a degree as other barriers. Many 

 animals can suffer with impunity an arctic or a tropical 

 climate ; the tiger is often regarded as a purely tropical 

 creature, but as is well known it extends its range to 

 Amurland, in northern China. At the Zoological Society's 

 Gardens the polar bears do not show any great mortality ; 

 a specimen once lived there in perfect health for 37 years. 

 Travellers have described monkeys leaping among the 

 snow-clad branches of pine trees upon the Himalayas. 

 Minute organisms have special facilities for passive mi- 

 gration. M. de Guerne 1 investigated the mud adherent to 



1 Comptes Rendus, Soc. Biol. 1888. 




136 OCEANIC ISLANDS. [CH. Ill 



the feet of wild ducks and found it to contain after 

 cultivation numerous small creatures such as Nematoda, 

 Rotifers, eggs of Cladocera, statoblasts of Plumatella &c. 

 Not only are the eggs of most of these creatures ex- 

 tremely patient of desiccation, but the animals them- 

 selves would readily survive a short journey. A series of 

 journeys would scatter them far and wide over the globe. 

 Such small aquatic organisms are known to be widely 

 dispersed. 



We find that the facts of distribution are quite in 

 accord with these principles. Birds and winged creatures 

 generally, such as bats, are on the whole the most widely 

 distributed orders of animals. Amphibia and earthworms 

 rarely or never occur on both sides of a stretch of sea 

 unless there be good evidence to show that a land 

 connection once existed. Oceanic islands which have 

 been formed de novo in mid ocean and are not detached 

 portions of pre-existing continents are almost invariably 

 free from such animals as are incapable of traversing the 

 sea. If sufficiently distant from any continent oceanic 

 islands are generally without mammals, reptiles and 

 amphibia, but have both birds and insects and certain 

 other invertebrates which are transported to them by 

 involuntary migration. 



Influence of geological terrain upon faunas. 



Not only the existence of forests or deserts or open 

 pampas are influential in favouring or checking the 

 advance of animals to fresh localities ; it is even held that 




CH. Ill] GEOLOGICAL STRUCTURE AND DISTRIBUTION. 137 



the geological structure of the locality has a great in- 

 fluence in the matter. Prof. Edward Forbes held that the 

 snails were decidedly influenced by such causes in their 

 range. Limestone is as might be supposed the most 

 favourable rock for their full development ; but according 

 to him a sandy soil is better than a clayey or slaty 

 substratum. Certain apparent exceptions to this general 

 statement are explained by the greater influence of 

 climate ; thus the Shetland Islands abound in limestone 

 and yet there is a paucity of shells; 011 the other hand the 

 island of Guernsey is populated by vast numbers of 

 specimens of a particular species of snail ; this is not due 

 to the unfavourable granite soil but rather to the favour- 

 able climate, which is a stronger influence than the soil. 

 Dr Gadow has recently put forward again the importance 

 of the geological terrain in affecting the distribution of 

 organisms. It is much more important thinks Dr Gadow 

 than temperature or altitude. His studies upon the 

 subject were made in Portugal, and communicated to the 

 meeting of the British Association at Bath in the year 

 1888. They relate principally to reptiles and amphi- 

 bians ; Dr Gadow found reasons for coming to the con- 

 clusion that for both these groups of animals the red 

 sandstone was by far the most favourable soil. There is of 

 course in these two cases no pretence that the soil has a 

 direct effect comparable to the limy soil which is stated 

 to be so advantageous to land Mollusca. 




138 AQUATIC EARTHWORMS. [CH. Ill 



Dispersal of Oligochseta. 



The involuntary migration of animals is mainly con- 

 fined to the invertebrates and smaller vertebrates. Some 

 of the former possess special facilities for being carried 

 about from place to place, and it is invariably the case 

 that these species or genera are the most widely dis- 

 tributed. We will commence with a few examples taken 

 from the terrestrial and fresh -water Annelids. Earth- 

 worms as already mentioned are not easily moved from 

 place to place except by their own exertions ; there is 

 here but little assisted emigration. Rivers it is true 

 could, and doubtless do, convey them for considerable 

 distances, as many if not all are capable of surviving a 

 prolonged immersion in fresh water. M. Perrier kept an 

 earthworm for some weeks in a vessel of water, and I have 

 made a similar though not so prolonged an experiment 

 myself. This however would not be of much use as a 

 distributing agent unless they were thus enabled to 

 traverse a desert otherwise impassable. It is possible 

 that in this way a peculiar genus of earthworms, Siphono- 

 gaster, distinguished by a pair of long appendages of 

 problematical use, has been able to pass from tropical 

 Africa to Egypt, the Nile serving as the path. It is 

 difficult however to see how earthworms could be conveyed 

 across the sea 1 . Floating trunks have been observed far 



1 In the case of this as in so many other groups oceanic islands require 

 more study. Earthworms do occur in oceanic islands, but it seems 

 probable that such widely distributed forms as Eudrilus eugenia 

 (St Helena) and Pontoscolex arenicola (Fernando de Noronha) have been 

 accidentally imported. 




CH. Ill] DISPERSAL OF OLIGOCH.ETA. 139 



out at sea and the} 7 often harbour even large mammals, 

 which may thus reach a comparatively distant spot ; but 

 unless the water remained absolutely calm during the 

 long period necessary for the drifting by currents so that 

 no splashing occurred the worms would probably be killed. 

 Icebergs on the other hand, which often rise high out of 

 the water, might conceivably be efficient vehicles for the 

 transference of these animals. Prof. Leidy found a small 

 worm frozen in a block of ice which recovered ; the worm 

 was a member of the family Enchytraeidae, but it is possible 

 that a small earthworm with a thick body wall might also 

 survive temporary freezing. The most active agents in 

 the transference of small animals from country to country 

 are however birds ; but in this case they could be of but 

 little use. The only way in which a migration of this 

 kind could be effected \vould be in the cocoon ; earth- 

 worms invariably deposit their eggs in chitinous cocoons 

 from which the young do not emerge until nearly adult. 

 But these are often deposited deepish in the ground, or at 

 the roots of grass, whence they would not be very likely to 

 be detached by, and to stick to, the feet of birds. The 

 case however is different with the aquatic Oligochaeta. 

 These worms are in the first place smaller than the 

 majority of earthworms, with smaller cocoons, which could 

 be more readily transported ; in the second place they are 

 deposited often at the margins of pools, where Limicoke, 

 ducks, and other birds are in the habit of dabbling. The 

 possibilities of successful migration by these means is 

 increased by the fact that whereas in earthworms it is the 

 rule for one or at most a limited number of individuals to 




140 RANGE OF ^OLOSOMA. [CH. Ill 



emerge from a single cocoon, the lower worms often 

 emerge in great quantities from a single cocoon ; a single 

 cocoon therefore conveyed to a new locality may be the 

 means of founding a perfectly flourishing colony. The 

 little genus <sEolosoma, distinguished by the brilliantly 

 coloured oil globules with which the skin is ornamented, 

 has, so far as regards one species at any rate, the power of 

 temporarily encysting itself 1 , it has thus a double chance 

 of carriage to a distant locality at the hands or rather at 

 the feet of birds. We find that these facts are in 

 accordance with the actual distribution of the animals 

 concerned. Earthworms as a rule are not found in 

 countries unless there is a reasonable probability of their 

 having reached them by their own efforts in traversing 

 the soil, while the aquatic Oligochaeta are often very widely 

 distributed. I have given a few instances of this above. 

 It has been also pointed out that many of the aquatic 

 Oligochseta possess other means of dispersal by birds in 

 addition to the cocoons. The setae are often such as 

 would readily adhere to any rough surface, owing to their 

 hooked and bifid tips and their considerable size in 

 proportion to that of the body. 



Dispersal of land and fresh-water Mollusca. 



This subject has been so recently and fully treated by 

 Mr Kew 2 that it is only necessary to make a few extracts 

 from his book. The extension of their range on the part 



1 Cf. Ann. and Mag. Nat. Hist. Jan. 1892, p. 12. 



2 The Dispersal of Shells. Int. Sci. Series, London, 1893. 




CH. Ill] MOLLUSCA OF PONDS. 141 



of fresh-water Mollusca can be studied in its most simple 

 aspect by a consideration of the faunas of artificial ponds 

 and of " dew ponds." The latter are, it should be explained, 

 artificial ponds dug and lined with concrete or chalk mud 

 for the convenience of cattle ; they are left to be filled by 

 rain, dew, and the condensation of mist. At first devoid 

 of inhabitants such ponds gradually become stocked, thus 

 proving a capacity for active or passive migration on the 

 part of the Mollusca. Careful and successive observations 

 have proved in a few cases the actual time in which a 

 given pond may become populous. An isolated pond 

 near Leeds investigated by Mr Nelson during the years 

 1860-63 yielded two bivalves, Sphcerium lacustre and 

 Pisidium pusillum, and two Gastropods, Planorbis nautilus 

 and Lymncea peregra. About 1873 an additional species, 

 Planorbis corneus, was discovered ; and finally ten years 

 later the Molluscan fauna was increased by six other 

 species. Now this particular pond was in no communi- 

 cation even in seasons of flood with any other pond or 

 stream ; hence its inhabitants must have arrived by some 

 other conveyance than running water. To be able to 

 travel at all, and we shall enquire immediately into the 

 means of dispersal, implies considerable tenacity of life, 

 principally in withstanding the fatal effect of a too thorough 

 desiccation. That this tenacity of life need not by . any 

 manner of means be underestimated in dealing with the 

 problem under review, is shown by the fact that an 

 Australian Unio " having already survived in a dry drawer 

 for 231 days, packed up (after being tested in water) and 

 forwarded to England, reached Southampton in a living 




142 MIGRATIONS OF MOLLUSCA. [CH. Ill 



state 498 days after its capture." This may serve as a 

 sample from a rich store of instances. 



Some aquatic Mollusca leave the water and travel over 

 the fields. This is the case for instance with Lymtwea 

 truncatula. Those that are not able in this way to travel 

 from pond to pond have to trust to vehicles which may be 

 animate or inanimate. Whirlwinds have been proved to 

 take up and deposit safely at a distance shoals of little 

 fish ; and not only fish but Mollusca a thundercloud at 

 Paderborn in Germany rained down crowds of the fresh- 

 water bivalve Anodonta anatina. More effective in ex- 

 tending the range of such Mollusca are birds and insects. 

 Canon Tristram on one occasion shot a mallard in the 

 Sahara to the feet of which were attached " the eggs of 

 some Mollusc probably Succinea." Mr Darwin proved by 

 suspending a duck's feet in an aquarium that the newly 

 hatched young of univalves will adhere, and might there- 

 fore be carried long distances. But on the other hand 

 there is little positive evidence that such a means of 

 transit is made use of in nature. Mr Kew enquired with 

 negative results from a large number of our leading 

 ornithologists whether shells had actually been found 

 adherent to the feathers or legs of birds. As a mere 

 matter of probability everyone is agreed that this method 

 of transit is feasible ; suggestions as to how it may take 

 place are unfortunately considerably in excess of records 

 of the actual event. Insects however have often been 

 taken with bivalve shells actually adhering to them ; "five 

 individuals at least," says Mr Kew, " of the water scorpion 

 (Nepa), a large flying bug, have been caught with shells 




CH. Ill] DISPERSAL OF MOLLUSCA. BY INSECTS. 143 



attached." The great water beetle Dytiscus has also been 

 proved to aid in the dispersal of fresh-water Mollusca, 

 while the small Notonecta, the " water boatman," belongs 

 to the same category. These insects are powerful fliers 

 and could certainly get from pond to pond even when 

 weighted with a small bivalve. It is bivalves that they 

 have been proved to convey, not univalves. Birds, newts 

 and toads have also been shown to act as the means of 

 dispersal of Lamellibranchs. The fact that these can and 

 do snap at and hold tight to any object that is thrust 

 between the two valves of the shell ensures their dispersal 

 in this way. 



The above facts enable us to understand the peopling 

 of isolated ponds. The distances to be traversed are so 

 small, that the means of dispersal appear to be quite 

 adequate. We now come to the more difficult question of 

 crossing arms of the sea or, it may be, wide tracts of 

 ocean. We must consider also the terrestrial as well as 

 the aquatic species. That both classes of Mollusca do 

 cross even the widest seas is shown by their occurrence in 

 oceanic islands; that this occurs but rarely is shown by 

 the peculiarities of oceanic island Mollusca as compared 

 with those of the nearest mainland, whence they have 

 been presumably colonised. It is noteworthy however 

 that those who know most about the group invoke a 

 former land connection where possible. Thus the Rev. 

 A. H. Cooke in considering the rich fauna of land Mollusca 

 of the Philippine Islands 1 , so varied upon the different 



1 P.Z.S. 1892, p. 447. 




144 HELIX DESERTORUM. [CH. Ill 



islands, discusses the problems offered entirely from the 

 point of view of former land connection. 



Such land Mollusca as are operculate can of course 

 close their shells and so endure with impunity events that 

 would be fatal to others ; even the temporary operculum 

 formed by Helix is effective in this way. It is important 

 too to notice that fresh-water Mollusca can in some cases 

 endure brackish water, but it is stated by both Darwin 

 and Wallace that adults and ova are immediately destroyed 

 by salt water. This is of course fatal to the theory that 

 floating timber and brushwood can convey fresh-water 

 Mollusca in safety from shore to shore. Ice on the other 

 hand may well be carrier; Anodonta and Succinea and 

 Paludina have been frozen and have survived after libe- 

 ration. With regard to land Molluscs their tenacity of 

 life has become almost proverbial through the famous case 

 of the Helix desertorum in the British Museum. More 

 important is the record that out of 100 land shells im- 

 mersed in the sea in a box pierced with holes for a 

 fortnight 27 recovered; but of these 11 (out of a total of 

 12) were the operculate Cyclostoma. Helix however may 

 sometimes survive a similar treatment. 



In this way it is possible, or, according to Prof. 

 Semper 1 , likely that ocean currents propelling tree trunks 

 or even " floating islands " such as are known in tropical 

 seas may have effected the dispersal of land shells. But 

 in such cases it must be often necessary that the Molluscs 

 in question had secreted themselves in the crevices of the 

 bark of trees, a habit which has been apparently assigned 



1 Animal Life. Int. Sci. Series. 




CH. Ill] ARION AND TESTACELLA. 145 



to them without too much reason. Animal agencies for 

 the dispersal of both land and fresh water shells for long 

 distances across the sea are practically limited to birds ; 

 and as has been already mentioned this method of trans- 

 port must be rare as it has been so seldom observed. The 

 dispersal of slugs is of course harder to understand than 

 that of snails, as they have no protective shell. And yet 

 they are found in such remote islands as New Caledonia, 

 New Zealand, the Auckland Islands and some of the 

 Mascarene Islands. Madeira and the Azores have Arion, 

 which Mr Cockerell says 1 "has some appearance of being 

 native," though he makes the significant additional remark 

 that "none of the species are peculiar 2 ." The slug Testacella 

 makes a temporary cocoon, as do the land planarians and 

 some earthworms, in which no doubt it can survive drought. 

 But this will not sufficiently account for dispersal over 

 the sea ; and sea water is fatal to slugs and their eggs. 

 The eggs however are sometimes deposited in hollow 

 trunks of trees, where even the animals themselves occa- 

 sionally hide. The various methods of migration used 

 by other Molluscs may possibly be effective in the case of 

 slugs ; but at present there is here more than anywhere 

 a lamentable want of actual fact. 



Dispersal of Amphibia. 



The migrations of the larger aquatic animals are more 

 difficult ; and yet they have not unfrequently a wide 



1 Geographical Distribution of Slugs. P.Z.S. 1891, p. 214. 

 3 Cf. p. 152. 



B. Z. 10 




146 THE EDIBLE FROG. [CH. Ill 



range, which means power of dispersal. The edible frog, 

 Rana esculenta, is a case in point. This species extends 

 from Great Britain, where however it is supposed to have 

 been introduced, in the West to Corea and Japan in the 

 East and to Algeria in the South. Its range in fact is 

 over the entire Palsearctic region ; but individuals from 

 Siam agree with Japanese specimens, so that the frog is 

 Oriental as well as PalaBarctic in habitat. In a paper 

 upon the distribution of this frog Mr Boulenger 1 quotes 

 14 synonyms, generic as well as specific, thus illustrating 

 the difficulties introduced into the study of geographical 

 distribution by imperfect acquaintance with zoological 

 fact. Intermediate forms however prove that there is but 

 one species, divisible into four varieties. It is a question 

 whether certain of these varieties which occur in the 

 same country and do not interbreed are not rather of 

 specific than varietal value ; but in any case they must be 

 derived from the same stock, and the eastern variety does 

 not overlap any of the western. These facts seem to 

 argue powers of extended migration hampered by infre- 

 quent opportunity. A river system appears to be, at least 

 as a rule, inhabited by an identical fauna throughout, 

 though its course may be, as is that of the Nile, from 

 tropical to temperate regions. But river systems are 

 isolated from each other by intervening mountains ; and 

 moreover the rapid streams at the source are not suitable 

 for Amphibian life ; hence a species which inhabited one 

 river system would not in the ordinary course of events 

 get within a measurable distance of the tributaries of 



1 P.Z.S. 1891, p. 374. 




CH. Ill] MIGRATIONS OF REPTILES. 147 



another river system. We can only understand the min- 

 gling of the faunas of two river systems by wide-spreading 

 floods or by alterations in mountain ranges. Mountain 

 ranges are necessarily modern, geologically speaking, 

 owing to the potency of the effects of subaerial denudation. 

 Different relations existed in river systems before their 

 upheaval; and it is probably to facts of this kind and 

 possibly also to whirlwinds that we must trust in reflecting 

 upon the migrations of the Amphibia, which cannot be 

 much carried about by birds, as they are absent from 

 oceanic islands 1 , even so close to the mainland as is 

 Fernando Noronha. 



Dispersal of Reptiles. 



It will be pointed out later that as a rule the only 

 terrestrial vertebrates of purely oceanic islands, if there 

 are any at all, are Reptiles. This necessarily argues that 

 Reptiles possess some power of crossing the sea which is 

 denied to other vertebrates. There are a certain number 

 of facts which favour this view. While there are com- 

 paratively few mammals which voluntarily take to the 

 sea, there are not a few reptiles which either live almost 

 habitually in sea water without any corresponding modi- 

 fication of structure, or which occasionally are met with 

 in salt water. 



1 There is however Bufo dialophus of the Sandwich Islands; it may 

 be that the strings of eggs produced by the toad are more portable by 

 birds than the masses of eggs of the frog. 



102 




148 MARINE CROCODILES. [CH. Ill 



Coupled with this series of facts, which will be dealt 

 with immediately, there is the tenacity of life of reptiles to 

 be constantly borne in mind. The most familiar example 

 of a Lizard which is almost entirely marine is the remark- 

 able iguanoid Amblyrhynchus of the Galapagos. Not 

 only does this lizard take long swims out to sea but it can 

 evidently only be drowned with difficulty. Darwin made 

 the experiment of sinking one to the bottom for several 

 hours, at the conclusion of which it appeared to be 

 uninjured. It is even a question whether the animals 

 may not possibly be able to respire oxygen dissolved in 

 sea water ; at any rate it seems certain that some other 

 reptiles, e.g. certain tortoises, can. The pharynx of a few 

 species, for instance the water tortoise Aspidonectes, is 

 provided with filamentary appendages, apparently attached 

 to the remains of the gill arches, which are full of blood 

 vessels and which enable the creature to breathe ; at any 

 rate this tortoise has been kept under water for the space 

 of 10 hours. It is held that these vascular tufts are the 

 homologues of the gills of the Amphibia, and it is quite 

 conceivable that this capacity for breathing oxygen dis- 

 solved in water may have been inherited by other reptiles 

 besides the tortoises. 



Apart altogether from theories there are other reptiles 

 besides the Amblyrhynchus which can swim with impunity 

 in sea water and which do so on occasions. 



The crocodiles of the present epoch are entirely fresh 

 water in habit ; but the majority of the extinct families 

 were on the contrary marine. From the ancient Belodon 

 downwards we meet with the remains of the crocodiles in 




CH. Ill] REPTILES AND OCEAN BARRIERS. 149 



marine strata, which in all probability indicates that they 

 were at least frequently in the habit of swimming out to 

 sea. It is not of course positive proof, for it might be 

 urged that we have to do merely with the remains of 

 crocodiles which had been washed down the rivers after 

 death. The interesting point in connection with these 

 habits of the more ancient crocodiles is that many living 

 crocodiles will take to the sea sometimes ; a crocodile has 

 been met with at a very long distance from land within 

 the last year or two a crocodile has been recorded at the 

 Cocos Islands, which must therefore have swum for a con- 

 siderable distance. 



Not only are there purely marine snakes, like the 

 poisonous Pelamys, but serpents which are habitually 

 terrestrial will make an occasional trip to sea. It is 

 stated the snake Tropidonotus tessellatus (allied to our 

 common Grass snake) which lives upon the shores of 

 Dalmatia will enter the sea. Even the cobra (Naia 

 tripudians) has been captured entangled in the anchor 

 chain of a ship 1 . Fresh water tortoises are by no means 

 always impatient of salt water. And finally as many 

 lizards and probably all snakes can swim in fresh water it 

 is quite a reasonable supposition that in some cases they 

 could survive a sea voyage. 



With these examples before us it is clearly incorrect 

 to say that lizards and serpents are incapable of passing 

 ocean barriers, which indeed their presence on oceanic 

 islands shows conclusively that they can do. Mr Wallace 

 while admitting that lizards possess some means of 



1 Cf. Simroth, Die Entstehung der Landthiere. 




150 FREQUENT AND INFREQUENT MIGRATION. [CH. Ill 



dispersal across the sea thinks that this migration is 

 effected involuntarily and in the egg state. As to in- 

 voluntary migration on the part of reptiles Mr Wallace 

 quotes the case of a boa constrictor which floated on a 

 cedar to the island of St Vincent, two hundred miles away 

 from its home, where it killed a sheep before it was itself 

 put an end to. 



Evidence of capacity for Migration on the part of 



a given animal. 



As Prof. Semper has acutely pointed out 1 the facilities 

 for migration possessed by an animal can be to a certain 

 extent measured by the amount of modification gone 

 through by obviously migrated individuals. Naturally 

 no clearly defined scale can be drawn up ; but if an 

 animal, say a Mollusc, can very readily cross the sea to an 

 oceanic island it will be likely that its descendants upon 

 the island will hardly, if at all, differ from the parent 

 stock upon the main land. The reason of course is that 

 migration being easy will be constant and frequent, thus 

 preventing the acquisition of new characters through 

 isolation ; the perpetual interbreeding with newly arrived 

 individuals of the parent race will securely keep the 

 progeny in the original mould. Of course other causes 

 must also come into play, but this fact cannot be without 

 significance. 



It has been already pointed out that Reptiles are rare 



1 Animal Life, Int. Sci. Series. 




CH. Ill] BIRDS OF OCEANIC ISLANDS. 151 



on oceanic islands ; indeed they are more often entirely 

 absent than present even in small numbers ; hence it 

 must be inferred that they have peculiar difficulties in 

 crossing a considerable expanse of ocean. When they are 

 met with upon oceanic islands, as for example in the 

 Galapagos, they have undergone considerable modification, 

 thus emphasising from another point of view the diffi- 

 culties of their transference. On the other hand birds 

 are of all animals the most liberally endowed with the 

 capacity of crossing long stretches of ocean ; correlated 

 with this the birds of oceanic islands are not always 

 greatly modified as compared with their nearest allies 

 upon the mainland ; this is particularly well shown in- 

 such birds as are in the habit of taking long flights ; the 

 Waders for instance of oceanic islands are but rarely of 

 different species from those of the adjacent continents. 

 On the other hand the finches and such like " small birds," 

 frequently arboreal, depending entirely or largely upon 

 vegetable food, and not in the least marine in their 

 proclivities are commonly much specialised upon oceanic 

 islands ; often indeed to such a degree that their affinities 

 are hard to interpret, as is particularly well shown in 

 the case of some of the Sandwich Islands' birds (for which 

 see below). 



Influence of human interference upon Migration. 



In considering the facts and problems of distribution 

 it is very important to eliminate the changes in faunas 




152 MAN AS A DISTRIBUTING AGENT. [CH. Ill 



due to the interference of man. Such islands as St 

 Helena have had their fauna and flora radically changed 

 by these means. 



But there are other cases in which man has probably 

 had an influence which are not quite so obvious as that 

 just cited. Many small land Mollusca are readily earned 

 by ships laden with timber or other material upon which 

 such animals are found ; and the same kind of argument 

 applies to numerous other cases. When therefore we find 

 an identical species upon the two sides of a wide ocean 

 or other barrier hardly to be crossed by the animal in 

 question, we must not at once assume that this is evidence 

 of past land connection, or of unsuspected facilities for 

 crossing the barrier; it may be merely a question of 

 transport by ships. A consideration of the distribution of 

 certain genera of earthworms will serve to illustrate the 

 kind of argument and tests which may be applied to sift 

 these cases. 



The continent of Europe, and, so far as it is known, 

 northern Asia and the whole of North America is chiefly 

 tenanted by members of the genera Allwrus, Allolobophora 

 and Lumbricus. There are but few other genera than 

 these met with in the regions named. But these same 

 genera also occur in every other part of the world. They 

 are abundant for example in South America and in New 

 Zealand. A gathering of earthworms from tropical regions 

 is in fact, so far as my own experience goes, rarely without 

 Lumbricidse. This might be urged as an argument for 

 the antiquity of this particular family ; but as a matter of 

 fact the structural relations of this family to others seems 




CH. Ill] EXTRA-EUROPEAN LUMBRICID^. 153 



rather to indicate that it is modern. Indeed the world- 

 wide distribution of the three genera is really in all 

 probability due to the interference of man and not to 

 their own unaided efforts. The reasons for this are 

 twofold. In the first place it is important to show that 

 accidental transference is possible. This is shown by the 

 fact that Wardian cases received at the Royal Gardens 

 Kew frequently contain earthworms which have been 

 included accidentally. 



In plenty of other ways could specimens be conveyed 

 in this way from one country to another. Now were the 

 occurrence of the same genera in so many and so distantly 

 separated parts of the world a fact due to natural causes 

 alone, we should expect to find some differentiation of 

 species. But this is precisely what we do not find. 

 Without a single exception 1 the Lumbricidae from extra- 

 European regions are identical with those of Europe ; 

 there is not even a variety known which is characteristic 

 of a foreign continent. This is an argument of great 

 force ; if this dispersal were of old standing, as it must 

 have been were it brought about by purely natural causes, 

 time would have elapsed to allow of some modification in 

 various directions. The second argument is derived from 

 a consideration of the actual range of the presumably 

 imported species in the country of their adoption. Dr 

 Michaelsen has pointed out that in South America, where 

 Lumbricida3 are very abundant, they are most abundant 

 in cultivated ground near to the coast, nearest to the point 



1 Unless Allolobophora Japonica. But of course Japan belongs to 

 the Palaearctic region. 




154 PAST AND PRESENT RANGE OF THE BEAR. [CH. Ill 



of disembarcation ; the further we recede from the coast 

 the rarer do the European Lumbricidae become ; in the 

 interior of South America they are not to be seen. Prof. 

 Spencer met with exactly the same state of affairs in 

 Australia; the gardens in the towns abound in Lumbri- 

 cidaB to the almost entire exclusion of the truly indigenous 

 forms; to find these the cities must be left behind. The 

 coincidence is too great to be passed over. This leads to 

 the inference that in the case of these particular genera 

 the forms met with outside the Palaearctic region perhaps 

 even including North America are due to carriage on 

 the part of man. Every case of a supposed wide distribu- 

 tion of a species should in the same way be submitted to 

 careful criticism before acceptation as a fact of distribution. 

 Mr Macpherson's record 1 of an African lizard in Cumber- 

 land and Dr Gray's statement of a young crocodile 

 hidden beneath a haystack need no special examination 

 to deny their claims to indigeneity ; but there are plenty 

 of cases like that of the earthworms just referred to. 



On a former page we have dealt with discontinuous 

 distribution as a phenomena explicable in various ways. 



An excellent instance of the discontinuous distribution 

 of a species due to the influence of man is afforded by the 

 common bear ( Ursus arctos) of Europe. And here we 

 can, which we could not in the last case, fill up the gaps 

 for ourselves with certainty and not merely with reason- 

 able probability. In a carefully coloured map illustrating 

 the distribution of the bear-like Carnivora Dr Greve 2 



1 The Natural History of Lakeland. 



- Zoo/. Jahrliicher, Vol. vi. Alt. f. Syst. 




CH. Ill] THE LYNX AND THE BEAR IN EUROPE. 155 



tints nearly the whole of the Palsearctic region with the 

 colour which he uses to express the range of this Carnivora. 

 He also indicates the tract of country from which this 

 bear has died out within the historic period. At the 

 present time there are several isolated patches to the 

 west and south of the country continuously occupied by 

 the animal, where it is still to be met with ; such as the 

 Pyrenees and a portion of Switzerland. These isolated 

 patches are in most cases connected with the main area 

 by regions from which the animal has recently retired. 

 Another map illustrates precisely the same kind of distri- 

 bution exhibited by the lynx. This animal has a range 

 almost co-extensive with Ursus arctos, but it does not 

 get into Japan, which the bear does. It persists as two 

 outliers in Western Europe almost exactly corresponding 

 to those of the bear. But a tract on the east coast of 

 Italy no longer inhabited by the lynx is still the home of 

 the bear. Cultivation and civilisation are no doubt the 

 cause of these gaps ; but it is curious that they should 

 have been more effective in the case of the smaller lynx 

 than the larger bear. 



The existing Distribution of land and sea considered 

 in relation to Zoological Geography. 



In considering the phenomena of distribution at the 

 present day, it is important to bear in mind that the 

 existing distribution of land and sea has on the whole 

 remained the same for very long periods, according to 

 some for as long a time as we have any cognizance of. 




156 THE PERMANENCE OF OCEANS. [CH. Ill 



There are, it is true, those who would evolve a continent 

 to account for the range of a genus of beetles ; but on the 

 whole the evidence is against any such radical views of 

 past changes in the positions of oceans and continents. 

 The superstition of Atlantis connecting Africa and America 

 has perhaps not quite died away; and Mr H. O. Forbes 

 would relegate the tropical island of Madagascar, not to 

 mention the colder and more southern regions, to the icy 

 clasp of the Antarctic continent. 



Evidence in favour of Permanence of Oceans. 



The evidence in favour of the permanence of oceanic 

 area as such has been recently summed up by Mr Blan- 

 ford 1 . The arguments are fourfold. 



I. It has been ascertained that the density of the 

 earth's crust below the deep oceans is greater than that 

 elsewhere. This leads to the inference that this has been 

 so always, because denudation, if the ocean bottom had 

 been ever dry land, would have removed this inequality. 

 The detritus washed away by the action of rivers, rain, 

 and such causes would have tended to equalise the density 

 of the land everywhere. Mr Blanford however points 

 out in criticism of this suggestion that the observations, 

 due to Archdeacon Pratt, were made only in the Indian 

 Ocean, and may perhaps not hold universally. The 

 argument therefore is not of that weight which may be 

 fairly attached to some other considerations. 



1 Presidential Address to Geological Society, 1890. 




CH. Ill] OCEANIC ISLANDS AND SUBMERGED CONTINENTS. 157 



II. It seems to be well ascertained that no oceanic 

 islands are formed of stratified rocks belonging to early 

 geological periods. They are in the main either of recent 

 volcanic or coral formation. Sir Archibald Geikie in 

 reviewing the Abbe Renard's petrological work upon the 

 rocks of the island of St Paul in the Atlantic in Nature 

 some years back entitled his review, " A search for a lost 

 continent with a microscope." But no amount of research 

 either with or without a microscope has ever revealed the 

 slightest traces of a pre-existing continent in the oceanic 

 islands of any of the great oceans. On the other hand it 

 has been found that certain islands, once regarded as 

 purely oceanic, are in reality not so. This is the case 

 for example with New Caledonia, which contains both 

 palaeozoic and mesozoic rocks, though it is isolated by 

 water exceeding 1000 fathoms in depth. But these few 

 instances do not invalidate the general conclusion. Yet 

 two possible criticisms must be borne in mind ; in the 

 first place we are not as yet in possession of all the 

 requisite knowledge about all the islands in question ; in 

 the second place we can imagine a subsidence of a large 

 continental tract which would leave above the surface of 

 the water no trace of its continental origin. If Africa, as 

 Mr Blanford points out, were to be submerged 2000 

 fathoms below the sea only a few elevations would remain ; 

 these are Mt Kilimanjaro, the Camaroons, and a few 

 other peaks ; these mountains it must be remembered 

 are purely volcanic in structure and would give no 

 clue to the fate which had overtaken the surrounding 

 land. 




158 CHALK AND OOZE. [CH. Ill 



III. The third argument is of equal force, or perhaps 

 of greater force, than the last. If the great ocean depths 

 have not always been permanent we should expect to 

 meet with, among the stratified rocks, evidence of deep-sea 

 deposits. Here again defective knowledge offers a way 

 out of the difficulty to those who choose to believe in a 

 thorough change from time to time of the existing 

 relations between continental areas and the great oceans ; 

 the fact that no continental deposits present any likeness 

 to deep-sea " oozes " and " clays " seems to prevent the 

 holding of such a theory ; but the matter requires to be 

 more thoroughly disproved. An exploration of certain 

 geologically little known tracts might reveal evidence in 

 favour of the view which is at present not forthcoming. 

 It was at one time held that there is a great likeness 

 between the chalk of the Mesozoic epoch and the globi- 

 gerina ooze now in course of deposition in certain tracts of 

 the ocean. Superficially this resemblance is not a little 

 striking; but a closer comparison dissipates the theory. 

 It is true that in the deep sea in regions where the 

 globigerina ooze is found certain animals exist which 

 are identical with or very closely allied to animals 

 characteristic of the chalk. The Echinoids with flexible 

 tests, numerous Cidarids, and the species of the Globi- 

 gerinse themselves bear out this statement. A careful 

 analysis however of the chemical composition of the ooze 

 and a comparison of the results thus obtained show 

 divergences which are of importance. The percentage 

 of carbonate of lime in chalk is from 94 98 / , while 




CH. Ill] OOZE OF SHALLOW WATER. 159 



in ooze from a depth of many fathoms in mid- Atlantic it 

 is only 43 79 / . Chalk has a very small quantity of 

 silica, alumina and insoluble debris, while in ooze there 

 is 10 43 / of these substances. 



IV. Dr John Murray found that the ooze from shallow 

 water resembles chalk much more nearly than that from 

 depths over 1000 fathoms. Prof. Agassiz has described a 

 shore deposit largely derived from the debris of coral rocks 

 which bears a very close resemblance to chalk : and it is 



t/ 



possible that the chalk of Europe was to some extent at 

 any rate formed from the denudation of the coral reefs 

 which were so abundant during the oolite period. The 

 most striking instance which appears so far to support the 

 contrary proposition is the Radiolarian earth of the 

 Barbadoes, and perhaps of some of the other West 

 Indian islands. This overlies unquestioned sandstones 

 of tertiary origin ; hence it follows that, since the be- 

 ginning of the tertiary epoch, the land immediately 

 surrounding those islands and the islands themselves 

 must have been depressed to a depth of at least 1000 

 fathoms. 



Evidence against the view that existing Oceans 

 have not largely changed their areas. 



There is another series of facts which have a bearing 

 upon the problems at issue, and which indicate, though 

 obscurely perhaps, a possibility that far back in time 

 there may have been a relative disposition radically 

 different from that now prevailing. 




160 RANGE OF GRAPTOLITES. [CH. Ill 



That this may have been so is suggested by two con- 

 siderations deduced from two classes of facts. In the first 

 place the former wider range of organisms than now is 

 well known. This has been held to imply a former pre- 

 dominance of more uniform conditions of temperature 

 and climate, but it may also perhaps be looked upon as 

 evidence of another kind, which we shall now enter into. 

 I quote from Prof. Heilprin's manual the fact that out 

 of 13 Silurian and 24 Devonian Brachiopods found in the 

 deposits of China 10 of the former and 16 of the latter 

 occur in European formations, a proportion which is not 

 only very striking, but almost inexplicable on the hypo- 

 thesis that the conditions of marine life in the several 

 regions were then precisely as now. 



Another example may be taken from the Graptolites. 

 This is a particularly useful example, for it enables us to 

 make use of the dilemma. It has been suggested that 

 the Graptolites flourished in deep water and that the 

 rocks which contained them are therefore true deep-sea 

 deposits. If this is admitted, then the question is settled 

 at once without any necessity to proceed further. But 

 if not, we have to account for the striking fact that out 

 of the 24 species of Graptolites from Australia no less 

 than 18 are species belonging to Canada and the United 

 States. 



Now we may contrast with the conditions that ob- 

 tained during the Palasozoic period those which obtain 

 at the present day. And the contrast is most thorough. 

 Prof. Heilprin remarks that out of " the 400 or more 

 species of molluscs inhabiting the Japanese waters it 




CH. Ill] ANTARCTIC CRUSTACEA. 161 



appears that not more than 20 are found on the west 

 coast of North America." The proportion, in fact, instead 

 of being three-fourths is one-twentieth. It will be re- 

 membered also, in estimating the significance of these 

 facts, that the coasts of Japan enjoy a climate and tempe- 

 rature that is not widely different from that which is en- 

 joyed by the coasts of the part of America brought into 

 comparison. 



We may take as another example the Isopod Crusta- 

 ceans of the antarctic region which have been investi- 

 gated by the " Challenger," " Gazelle," and recently by the 

 German Polar expedition, the results of all these expedi- 

 tions having been carefully reported upon by Dr Pfeffer. 

 He enumerates 55 marine species of which only five have 

 at all an extensive range, and two of these, which are 

 stated to inhabit at once the shores of Patagonia and of 

 Rio Janeiro, are queried. As to a more northward ex- 

 tension there are no species which show any signs of it. 

 The genera enumerated are in all 27 ; and out of these 

 11 are limited to the southern ocean in the antarctic area. 



So much then for the first series of facts, which is that 

 the wide past distribution of marine animals contrasts 

 with the present limited distribution of the same, even 

 along areas which have very similar climatal conditions. 



Many geologists, including Mr Mellard Reade 1 , have 

 pointed out the extreme similarity between the con- 

 temporaneous or supposed contemporaneous rocks in 

 different parts of the world. When we "consider the 

 rocks." says the last-mentioned observer, " constituting the 



1 Natural Science, 1894. 

 B. Z 11 




162 SEAS OF CARBONIFEROUS PERIOD. [CH. Ill 



Carboniferous formation, the persistence of characteristics 

 over large areas of the earth's surface is most striking. 

 The repetition of coals, sandstones and shales in the 

 Carboniferous rocks of the North American continent 

 and in that of Great Britain seems almost to point to a 

 common origin." And this is by no means the only 

 example that could be adduced of the closest lithological 

 analogies between contemporaneous rocks in widely sepa- 

 rated localities. 



These two series of facts almost seem to lead at once 

 to the conclusion that we have here evidence that in, say 

 the Carboniferous period, there was a tract of ocean con- 

 tinuous from east to west of not great depth, which would 

 point to adjacent land and set aside the theory that the 

 deep oceans of to-day have always been practically the same. 



But there are some criticisms to consider first. It has 

 been objected to the question of contemporaneity, let 

 alone the continuity, in a given formation that it is im- 

 possible strictly speaking, since organisms take time to 

 migrate. A given species comes into existence let us 

 suppose in the Australian district; it has to get to the 

 European seas where it may be also found ; the time that 

 elapses while this journey is made is longer or shorter ac- 

 cording to the distance and to the variety and difficulty 

 of the obstacles. " For anything that Geology or Paleonto- 

 logy is able to show to the contrary," wrote Prof. Huxley, 

 " a Devonian fauna and flora in the British Islands may 

 have been contemporaneous with Silurian life in North 

 America and with a Carboniferous fauna and flora in 

 Africa." 




CH. Ill] SYNCHRONOUS FAUNAS. 163 



In this case it would necessarily follow, on account of 

 the disparity of age, that there need be no similarity in 

 conditions between the different parts of the world during 

 the same geological period. Prof. Nicholson 1 , accepting 

 this criticism, observes, " Most of the facts bearing upon 

 this question may be elicited by a consideration of such a 

 widely extended and well-known formation as the Moun- 

 tain Limestone or Sub-Carboniferous Limestone. This 

 formation occurs in localities as remote from one another 

 as Europe, Central Asia, North America, South America 

 and Australia; and it is characterised by an assemblage 

 of well-marked fossils, amongst which Brachiopods be- 

 longing to the genus Productus may be specially singled 

 out. Now if we believe that the Carboniferous Limestone 

 in all the widely distant localities was strictly contempo- 

 raneous, we should be compelled to admit the existence 

 of an ocean embracing all these points, and in spite of its 

 enormous extent so uniform in temperature and depth 

 and the other conditions of marine life, that beings either 

 the same or very nearly the same inhabited it from end 

 to end." These two statements are ingeniously met by 

 Prof. Heilprin. They imply, he says, that every animal 

 has migrated in exactly the same way and direction. 

 And it is hardly conceivable, in fact impossible, that this 

 can have been everywhere the case. " Given the possible 

 equivalence in age, as is argued, of the Silurian fauna of 

 North America with the Devonian of the British Isles, 

 and the Carboniferous of Africa or any similar arrange- 

 ment, why has it never happened that when migration, 



1 Manual of Paleontology. 



112 




164 ANTARCTIC CONTINENT. [CH. Ill 



necessitated by alterations in the physical condition of the 

 environs, commenced, a fauna with an earlier facies has 

 been imposed upon a later one, as the Devonian of Britain 

 upon the Carboniferous of Africa, or the American Silurian 

 upon the British Devonian ? " The migration of one 

 animal might have been in one direction and the migra- 

 tion of another in the reverse direction. 



Besides the migration of animals can hardly be sup- 

 posed always or often to occupy a space of time that 

 could be fairly compared to a geological period. Especially 

 is this the case with marine creatures whose powers of dis- 

 persal are so much greater than those of terrestrial animals. 

 The Indo-Pacific fauna for example is widely spread at 

 the present day ; and formations now being laid down at 

 the extremities of this vast area are not only synchronous 

 but will entomb the remains of largely similar organisms, 

 often of identical species. 



These general considerations lead to the discussion of 

 the following particular examples of a possibly greater ex- 

 tension of land in past times through what is now deep sea. 



Evidence in favour of a formerly more extensive 



Antarctic Continent. 



Faunal conditions in the southern hemisphere have 

 recently been applied again to the question of a former 

 northward extension of the antarctic continent. The 

 evidence has been brought together by Mr H. O. Forbes 1 . 



1 Proc. Roy. Geog. Soc. 1894. 




CH. Ill] FORMER EXTENSION OF ANTARCTICA. 165 



The continent at present is entirely ice-bound, and 

 though of great size, about twice as large as Europe, does 

 not bulk largely upon most maps ; this is due to the small 

 extent of coast line which has been explored. At present 

 the antarctic continent is probably almost entirely with- 

 out a terrestrial fauna by reason of course of its rigorous 

 climate. 



Mr Forbes boldly draws imaginary land tracts connect- 

 ing this region with the adjacent continents of Africa, 

 America and Australia. There is certainly some evidence 

 in favour of such a connection having once existed. There 

 are however numerous facts which appear to negative 

 such an idea. The negation however is possibly more 

 apparent than real. It has been pointed out that the 

 ocean which separates the south polar continent from any 

 other land is of great depth, and all those arguments for 

 the permanence of the great oceans apply in this case as 

 in the others dealt with on a previous page. But it must 

 be admitted here as in so many cases that our knowledge 

 of ocean soundings is far from complete ; Mr Blanford 

 points out 1 that south of Africa there are no soundings 

 and that therefore we are at liberty in the meantime to 

 regard as possible the existence of a bank uniting the 

 two continents of no greater depth than the Mozambique 

 channel. It is however rather New Zealand and Pata- 

 gonia which are allied in their fauna than either of them 

 with the southern parts of Africa ; resemblances between 

 tropical Africa and tropical America have been dealt with 

 on another page (p. 112). These likenesses in a few cases 

 1 Presidential address to Geol. Soc. 1890. 




166 PENGUINS. [CH. Ill 



amount to positive identity of species ; and moreover of 

 species whose identity is exceedingly remarkable in rela- 

 tion to the problem offered for solution. 



That the Penguins should extend throughout the 

 whole antarctic area from New Zealand to Patagonia is 

 not so remarkable a fact ; there is no need of evolving 

 a continent for the convenience of these almost marine 

 birds, or even to explain the wide range of the purely ant- 

 arctic Ckionis. Nor do the arguments, such as they are, 

 which are to be derived from a study of the range of the 

 living " struthious " birds appear to have overwhelming 

 force ; both Penguins and struthious birds are in all pro- 

 bability the remnants of ancient types ; and their relega- 

 tion to the southernmost half of the globe is as much 

 in accord with the polar origin of life dealt with elsewhere 

 as with a former extensive antarctic continent. Besides 

 the struthious birds are not now regarded as belonging 

 to one family ; they seem really to form an assemblage 

 of the remains of more than one family. The distribution 

 of the struthious birds both living and extinct may 

 be brought forward as evidence of the former north- 

 ward extension of the antarctic continent. Recent dis- 

 coveries in the Argentine have an important bearing upon 

 the matter ; the evidence takes us back to the middle and 

 even to the beginning of the tertiary period ; this how- 

 ever is nothing to be surprised at ; the connection between 

 the existing land masses and the antarctic continent, if it 

 ever existed at all, must have been very ancient, as the 

 stretch of ocean now dividing them is so wide. As is 

 unfortunately the rule with extinct species known by 




CH. Ill] STRUTHIOUS BIRDS. 167 



remains which are in various degrees fragmentary, the 

 actual number of the genera and species is doubtful ; but 

 it seems now to be well established that there were in the 

 more southern regions of the American continent at least 

 three genera of gigantic flightless birds comprising seven 

 or eight species. To these genera the names of Brontornis, 

 Phororhacus and Opisthodactylus have been applied. Some 

 of these birds were actually the largest known forms of 

 Ratites. It appears from certain roughnesses on the 

 bones of the skull that some species bore upon the head 

 a casque like that of the Cassowaries ; though in some 

 respects, thinks Mr Lydekker, the resemblances are with 

 the living and South American Psophia and Cariama 1 . 

 They approximate however to the Dinornithidse in a 

 number of characters which together are of some im- 

 portance ; thus there is with them as in the Dinornithida? 

 a bony bridge over the extensor groove of the tibia, and 

 the general proportions of the tibia and tarso-metatarsus 

 are like those of the same bones in the Dinornithidse. 

 But the significance of the facts from the point of view 

 of Zoogeography is somewhat blurred if we rightly refer 

 to the Ratites, or Platycoracoidese, as Fiirbringer calls 

 them, the European genera Gastornis and Dasomis and 

 the American Diatryma. Fiirbringer however queries 

 the inclusion of the two last in the group, and does not 

 allow Gastornis there at all. Dasomis is only known by 

 an imperfect cranium, and Diatryma by an incomplete 

 tarso-metatarsus, so that this evidence is not at present 



1 See a paper by Lydekker in Ibis for 1893. 




168 TERRESTRIAL ANNELIDS. [CH. Ill 



necessarily fatal to the evidence offered by the un- 

 doubtedly struthious Argentine birds. 



As with the Sea-lions, also practically confined to the 

 southern hemisphere, the explanation of the range of 

 the Penguins is possibly rather one of temperature. The 

 Sea-lions are strong swimmers, and have been met with 

 far from land ; indeed the " Sea-serpent" is possibly partly 

 compounded of a large sea-lion. Currents too would assist 

 in the dispersal of these animals without any recourse to 

 a continuous coast-line to aid in migration. M. Milne 

 Edwards, whose name is particularly to be associated with 

 the idea of an antarctic region, has pointed out that 

 marine currents flow from the polar region in all direc- 

 tions northward ; with the aid of these currents, reinforced 

 by floating ice, which is known to reach land abutting 

 upon the southern ocean, we can understand the peopling 

 of Kerguelen and other regions with the birds and 

 mammals referred to. Mr Wallace while naturally ad- 

 mitting the resemblances between various tracts of land 

 in the southern hemisphere is disposed to rely upon float- 

 ing masses of ice to account for the facts. It is difficult 

 to apply this solution of a puzzling problem to the case 

 of the terrestrial Annelida of the antarctic area. It is a 

 curious fact that Mr Forbes with the material before him 

 did not use the strongest argument that could be used 

 in favour of his views ; since those papers were written 

 the evidence has moreover increased. The earthworm 

 fauna of New Zealand is perhaps as well known as is that 

 of any extra-European region. That our knowledge is 

 approaching completion is shown by the fact that collec- 




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CH. Ill] ACANTHODRILUS. 169 



tions from that part of the world do not so frequently as 

 formerly contain new species. This fauna consists prin- 

 cipally of species of the genus Acanthodrilus. There are 

 three genera of the same family peculiar to New Zealand, 

 viz. Octochcetus, Plagiochceta and Deinodrilus. All these 

 worms form a very well-marked family which is character- 

 ised by the fact that the male sperm ducts open on to the 

 xvinth segment of the body, and that on to the two seg- 

 ments in front of and behind this open a pair of coiled 

 tubular glands accompanied by a bundle of modified 

 " penial " setae. The bulk of the species of Acanthodrilida? 

 belong to the genus Acanthodrilus itself. Besides this 

 genus there are three species of quite a different genus, 

 Microscolex. This genus is referable to another family 

 allied however to the Acanthodrilidae. There is here only 

 one pair of tubular glands which open in common with or 

 or very close to the sperm ducts upon segment xvn. The 

 penial setae also exist. The remaining Oligochceta tern- 

 coke of New Zealand, apart from introduced Lumbricidcv, 

 are a few species of Perichceta, or rather a closely allied 

 genus which I have named Diporochceta. In the more 

 southern parts of the South American continent precisely 

 the same families are met with ; and not only that, but 

 the same genera. Dr Michaelsen of Hamburg has recently 

 made a voyage to that part of the world, and has brought 

 back with him a very large collection of earthworms; 

 these belong, with the exception of introduced Lumbricidcv 

 and a single Perichcvta, exclusively to the genera Micro- 

 scolex, Acanthodrilus and Kerria (a near ally of Acantho- 

 drilus). So far as we know at present not a single species 




170 MICROSCOLEX. [CH. Ill 



from America is identical with any New Zealand form ; 

 but they are all closely related. This however does not 

 exhaust the antarctic region. During the voyage of the 

 " Challenger " and the transit of Venus expedition a few 

 earthworms were collected at Kerguelen and at Marion 

 Island. These amounted to only a single species, which 

 is common to both islands, and is a member of the genus 

 Acanthodrilus. The same genus also occurs in South 

 Africa ; but Africa so far as concerns the family Acantho- 

 drilidce chiefly abounds in the genus Benhamia, which 

 differs in a few small though constant points from 

 Acanthodrilus. The genus Benhamia in the opinion of 

 Dr Michaelsen, is really limited to Africa. Species have 

 been described from America, the West Indies, and from 

 India and Malaya ; but it is possible, as Dr Michaelsen 

 thinks, that they have been imported by man. The 

 family AcanthodrilidoB indeed is almost exclusively ant- 

 arctic, and in any case by far the majority of its species 

 and genera are limited to the antarctic area. Microscoleoc 

 passes into North America, has been met with in Europe 

 and the Azores and Canaries, and also occurs in Australia. 

 But with the exception of America all the species found 

 outside the antarctic area are identical with species living 

 within it 1 ; this suggests importation from abroad. This 

 series of facts is a very remarkable one, and deserves more 

 consideration than has been devoted to it in forming any 

 theory about a possible former antarctic continent of greater 

 dimensions than the present shrunken land mass. The 

 facts seem also to point to a more recent communication 

 1 Excepting M. poultoni from Teneriffe and M. algeriensis from Algeria. 




CH. Ill] FRESH-WATER FISH. 171 



between Patagonia and New Zealand than between either 

 of these countries and the Cape of Good Hope. These 

 however are by no means the only facts which seem to 

 point to some read} 7 method of transit between these 

 different regions for purely terrestrial or fresh-water 

 animals. Many writers have with justice emphasised the 

 extremely significant fact that the fresh- water fish Ga- 

 laxias attenuates occurs in Tasmania, New Zealand, the 

 Falkland Islands and the southern extremity of the South 

 American continent. This is perhaps the only case of a 

 species of fish with so wide a range in the antarctic hemi- 

 sphere ; but the two families of Salmon oid fishes Ga- 

 laxiidcv and Hoplockitonidce are restricted to the same 

 countries with the addition of southern Australia. A 

 species of Galaxias has recently been described from 

 India ; but Mr Blanford states that the determination is 

 doubtful. Now a fresh-water fish, even more if possible 

 than the purely terrestrial OligocJiceta, needs a continuity 

 of free land surface for its migrations 1 . And the fishes of 

 these two families form a considerable proportion of the 

 entire fish fauna of the countries where they occur. It 



/ 



is well known, of course, that the ova of many fish, par- 

 ticularly of Salmonoids, can be safely transferred in ice 

 and will hatch out at the other end : rivers in New 

 Zealand have been stocked in this very way. So that 

 there is no antecedent improbability in the iceberg theory 

 of the migration of these fishes. But in this case it is 



1 The possibility however must be borne in mind that they have been 

 independently evolved from marine ancestors. This can hardly perhaps 

 apply to Galaxias attenuates, to the same species. 




172 FROGS OF AUSTRALIA. [CH. Ill 



remarkable that oceanic islands which happen to be within 

 the districts visited by icebergs have not also been stocked 

 with fish. This criticism it will be seen cuts both ways. 

 We cannot apply it to continents, if we are forbidden to 

 consider it in connection with oceanic islands. It has 

 already been pointed out in connection with the same 

 subject of oceanic islands that they are invariably desti- 

 tute of frogs or of amphibians of any kind. These crea- 

 tures are quite powerless to migrate across the sea. Now 

 a family of frogs, the Cystignathidce, are common to South 

 Australia and to South America. I do not think it 

 prudent to lay any particular stress upon the likeness 

 in the Coleopterous fauna of the antarctic parts of the 

 world ; for beetles or their larvae can with comparative 

 ease be carried about by that convenient deus ex machina, 

 the floating log ; more remarkable is the negative fact 

 that the land shells do not support the idea of a former 

 extended antarctic continent. Precisely the same facilities 

 are enjoyed by the terrestrial mollusca for dispersal as by 

 insects. It is however difficult to extract anything of 

 value out of this fact either in favour of or against the 

 view that the antarctic current had formerly a greater 

 extent to the northward. It is perhaps to be correlated 

 with the fact that there is only a single land shell in Ker- 

 guelen, which would seem to be some indication that in 

 this quarter of the globe some hindrance exists to the 

 migration of these animals. The matter must remain 

 unexplained for the present. 



The distribution of the Isopod genus Scrolls may be 

 cited as further evidence in the same direction ; by some 




CH. Ill] SPECIES OF SEROLIS. 173 



it is made the type of a distinct family of that group, and 

 it is in many respects peculiar ; the outward form recalls 

 that of the extinct Trilobites " An protypon Entomolo- 

 thi ? " asks Fabricius, and attempts to reinstate the genus 

 in the neighbourhood of those long defunct Arthropods 

 have lately been made. Apart from this spurious claim 

 to interest, Serolis has a genuine attractiveness by reason 

 of its remarkable geographical range. It may be ex- 

 plained in the first place that Serolis or the Serolidae, if 

 the family be approved of differs from all other Isopods 

 in the facts that (1) the first two segments of the thorax 

 are more or less completely united with the cephalic 

 shield, (2) that the last three segments of the abdomen 

 are fused with the telson, (3) the wide depressed body 

 with usually elongated epimera. This assemblage of 

 characteristics divides the Crustaceans in question from 

 others. 



There are in all twenty-six species of the genus, of 

 which perhaps some (those queried) are a little doubtful. 

 They are thus distributed : 



(1) Off Pernambuco (675 fathoms), Serolis gracilis 1 . 



(2) Off Pernambuco (410 fathoms), Serolis ant- 



arctica. The same species also found in 1375 

 and 1600 fathoms near Crozets. 



(3) Off Rio Janeiro in 600 and 2040 fathoms, Serolis 



necera. 



(4) Off antarctic continent, near New Zealand in 



410 1975 fathoms, Serolis bromleyana. 



1 For a full account of this genus see Beddard, Report Zool. ChalL 

 Exp. Vol. XL, and Pfeffer, Jahrb. Hatttb.wiss. Anstalt. 1888. 




174 SEROLIS OF AUSTRALIA. [CH. Ill 



(5) Serolis paradoxa, Patagonia, Falkland Islands, 



New Zealand (?), Senegal (?) 



(6) ? Serolis trilobitoides, South Shetlands, Patagonia. 



(7) Serolis gaudichaudi, Chili. 



(8) Serolis planus, Patagonia. 



(9) Serolis convexa, Patagonia. 



(10) Serolis schythei, Patagonia, New Zealand (?). 



(11) Serolis septemcarinata, Marion and Prince Ed- 



ward Islands, Kerguelen, S. Georgia. 



(12) Serolis latifrons, Kerguelen, Crozets, Auckland 



Island. 



(13) Serolis cornuta, Crozets, Kerguelen. 



(14) ? Serolis serrei, Patagonia. 



(15) ? Serolis acutangula, ? locality. 



(16) Serolis pagenstecheri, S. Georgia. 



(17) Serolis polita, S. Georgia. 



(18) Serolis carinata, California. 



(19) Serolis tuberculata, Bass' Strait. 



(20) Serolis australiensis, Australia. 



(21) Serolis elongata, Australia. 



(22) Serolis pallida, Australia. 



(23) Serolis longicaudata, Australia. 



(24) Serolis minuta, Australia. 



It will be noted that four are deep sea forms ; and we 

 postpone consideration of these ; for it is well known that 

 the deep sea fauna must be studied by itself. The 

 remaining forms are absolutely confined to the antarctic 

 region and to the south coast of Australia, with the 

 doubtful exception of Serolis paradoxa and $. carinata. 




CH. Ill] DISTRIBUTION OF SEROLIS. 175 



They are most prevalent on the coasts of Patagonia. A 

 few, but very few, species range widely through the 

 antarctic region; thus 8. septemcarinata extends from 

 S. Georgia to Kerguelen. The Australian species, with 

 the exception of Serolis minuta, form a well-marked 

 assemblage to which perhaps a different generic name 

 ought to have been given ; these species differ from the 

 typical species of the genus in the fact that the dorsal 

 part of the sixth thoracic segment is absolute in the 

 middle line ; there are also other smaller particulars in 

 which these Australian species diverge from the normal 

 structure of the genus. 



Here we have a family of curiously restricted range ; 

 it is exclusively antarctic, not getting so far north as the 

 equator. It may be surmised that the genus came into 

 being in the antarctic region ; whence conditions of 

 temperature did not allow it to migrate. But a difficulty 

 is presented by the wide range within this area of species 

 which being addicted to shallow water would find some 

 hindrances in crossing the thousands of miles of deep 

 water which part Patagonia from the Crozets. Possibly 

 this difficulty is removed by the supposition that in former 

 times the antarctic continent extended further north than 

 it does now, thus enabling the species to wander far 

 without altering greatly the surrounding conditions. The 

 marked differences which distinguish the Australian 

 species from their more southern allies are so far a proof 

 of the more remote period at which a migration to the 

 shores of Australia was possible. A .cold current, which 

 sweeps up the western shores of South America, may 




176 MADAGASCAR. [CH. Ill 



have carried with it the single species 8. carinata, which 

 extends to so northerly a situation. 



" Lemuria." 



By some naturalists, Madagascar is believed to be the 

 remnant of a great continent extending across the Indian 

 Ocean, and has been referred to as Lemuria. Some of the 

 islands lying to the north of Madagascar will be in this 

 event other scraps of the same continent. Among these 

 islands the Seychelles at least offer other evidence of 

 being the last fragment of a vanished continental expanse : 

 they are a group of about thirty islets lying 700 miles to 

 the north of Madagascar. Though oceanic in most of 

 their characters they are composed of ''granitoid or 

 gneissoid " rocks, thus arguing original continental con- 

 ditions. In spite of this fact in their geological structure 

 they do not possess a single indigenous mammalian 

 inhabitant. This fact, it may be incidentally pointed out, 

 is of importance ; it shows that the true remains of 

 continents may be without mammals and that the absence 

 of mammalia is not always to be relied on as an infallible 

 sign of an oceanic island. Their small size may have 

 caused the decay of the original mammalian fauna, an 

 argument that can of course be applied to the doubtful 

 case of the Galapagos archipelago (see below). There are 

 however four Amphibia, a more infallible sign of a former 

 continental connection. These are a frog, Rana mascarina, 

 which is widely distributed in this region of the world, 

 a peculiar Tree frog and two Csecilians, that group of 




CH. Ill] MASCARENE BIRDS. 177 



tailless and underground Amphibia particularly character- 

 istic of Ceylon. Mr Blanford instances the Seychelles as 

 the only thoroughly authenticated case of an oceanic 

 island composed of granitoid rocks. This however only 

 takes us necessarily as far as a possible former connection 

 with Madagascar, which Mr Wallace admits, though pre- 

 mising that if this and the other island groups in the 

 neighbourhood were ever connected with each other and 

 with Madagascar "it was probably at a very remote 

 period." There now remain the characters of the fauna 

 of the Mascarene region for consideration. So far as 

 concerns the Mammals and Birds the evidence is not so 

 strong, or rather it need hardly be considered as any indi- 

 cation of a former connection with India. 



The mammals, as has been already pointed out, are 

 either African or altogether peculiar, chiefly the latter. 

 It is true that there are Oriental birds in Madagascar, 

 but these are, as Mr Wallace acutely points out, " slightly 

 modified forms of existing Indian genera or... species 

 hardly distinguishable from those of India." This argu- 

 ment, triumphantly adduced by Dr Hartlaub as evidence 

 of the former " Lemuria," really points precisely the other 

 way. Apart altogether from the ready means of migration 

 possessed by birds birds offer most unreliable evidence 

 in proving a matter of this kind we should expect on the 

 hypothesis of a former land connection with India not to 

 find such close resemblances ; what is wanted to prove 

 the theory of those who believe in "Lemuria," and use 

 birds to support their theory, is to discover Mascarene 

 birds which though presenting certain likenesses to those 



B. Z. 12 




178 AMPHIBIA AND FISHES. [CH. Ill 



of India should be widely different as to species and 

 genera, showing a great divergence which would have 

 naturally occurred in the time during which India and 

 Madagascar have been, on any hypothesis, divided. 



If however we turn to other groups of the animal 

 kingdom, the rejection of the hypothesis of a former 

 connection between India and Madagascar does not appear 

 to be so reasonable. For example, the Amphibia are not 

 to be passed over; there are according to Mr Blanford, 16 

 species of the genus of frogs Rhacophorus, all the other 

 species being Oriental. The genus Calophrynus has three 

 species, of which two are Oriental and one Mascarene. 

 The family Discophidse comprises seven genera and thir- 

 teen species in Madagascar ; the only other member of 

 the family is Burmese. Among fresh-water fishes Mr 

 Blanford calls attention to a remarkable instance of an 

 intermediate form being a native of Madagascar. It is a 

 peculiar genus, named Paretroplopus, belonging to the 

 family ChromididaB and intermediate between the African 

 genus Hemichromis and the Oriental genus Etroplus. 

 This family of fishes is especially characteristic of Africa, 

 and is also found in South America. It is rarer in the 

 Oriental region. The facts that Mr Blanford has laid 

 stress upon seem to indicate, as he remarks, that there 

 have been in this family of fishes two lines of migration 

 from Africa to India. One by way of the Nile into 

 Palestine, where the family occurs ; the other through 

 Madagascar, leaving behind evidence of its passage in the 

 shape of the genus referred to which has so to speak not 

 quite attained to the Asiatic character. The importance 




CH. Ill] MOLLUSC A OF SEYCHELLES. 179 



of the evidence offered by spiders is emphasized by M. 

 Simon's removal of Madagascar from the Ethiopian and 

 its transference to the Oriental region l . 



The land and fresh water Mollusca are a doubtful 

 group with which to have many dealings of the present 

 kind ; they are not so reliable as many, owing to the fact 

 of their possessing a shell which has made them the 

 objects of collectors who often do no more than refer to the 

 " animal " as if it was a casual and unimportant inhabitant 

 of the shell But their evidence, so far as it can be read, 

 is not without bearings upon the problem that we are 

 now engaged in. A large proportion of the land Mollusca 

 are peculiar ; and there is, as in the West Indies, a great 

 development of the Cyclostomatidse. In this latter family 

 a genus Cyclotopsis is limited to the Mascarene islands 

 and to the Indian peninsula. In the Seychelles we have 

 Cyathopoma and Leptopoma, which are also Oriental 

 genera, and Helicina, which is almost world-wide but not 

 African. The two families to which these belong, Cyclo- 

 phoridse and Helicinidae, " must apparently," says Mr 

 Blanford, " have reached the Seychelles from the eastward, 

 for not one of them is found in Africa." 



Mr Blanford deals with the obvious suggestion that 

 the presence of these animals may be recent and due to 

 floating trees or the like. The currents however indicate 

 that the transference of such small creatures would be 

 from the Seychelles to India and not in the reverse 

 direction. Another possible method of colonisation by 

 the help of winds is not to be considered ; for it appears 

 1 Trouessart, La Geographic Zoologique, p. 210. 



122 




180 EARTHWORMS OF MADAGASCAR. [CH. Ill 



that great wind storms, prevalent in this part of the world, 

 do not cross the equator, which they would certainly have 

 to do in order to convey animals or their eggs from India 

 to the Seychelles. The earthworms of Madagascar are 

 unfortunately not at all well known. But what we do 

 know supports the facts brought together and emphasized 

 by Mr Blanford. There is in the island at least one 

 peculiar genus. This has been termed by Dr Michaelsen 

 Kynotus, and it contains three or four species. The only 

 other earthworms known from Madagascar are Perrier's 

 Acanthodrilus verticillatus and Perichceta madagasca- 

 riensis and P. indica. The former worm is only very doubt- 

 fully an Acanthodrilus', I bring forward reasons in my 

 forthcoming Monograph of the Oligochaeta for referring it 

 to the already mentioned genus Kynotus, with one of the 

 already described species of which it may be identical. 

 Perichceta madagascariensis is closely allied to, if not 

 identical with Megascolex armatus, a common Indian form. 

 Perichceta indica is not far from being a cosmopolite. 

 Now the genus Kynotus belongs to the family Geosco- 

 licidae, which is distributed through tropical South 

 America and the West Indies, tropical Africa, and certain 

 parts of Malaya; it just gets into Europe. But the old 

 world forms can be separated from those of the new world 

 to so marked an extent that it is permissible to divide the 

 family into two subfamilies. The spermathecse in the old 

 world forms if present at all, and they are occasionally 

 absent altogether, are very numerous and minute, while 

 those of the American genera are the usual paired 

 structures which are so characteristic of the Oligochaeta. 




CH. Ill] EARTHWORMS OF MAURITIUS AND RODRIGUEZ. 181 



The bulk of the old world genera of Geoscolicidse are 

 Oriental ; and it may be fairly said that Kynotus is at 

 least as nearly allied to them as it is to the African genera, 

 Another possibly important piece of evidence to be 

 derived from this group of animals is the existence in the 

 Seychelles of a species, which I have dissected and cannot 

 distinguish from the Oriental Megascolex armatus, already 

 referred to. But this worm, if truly indigenous, indicates 

 obviously a migration from India. In the Mauritius and 

 in Rodriguez are species of the characteristically Oriental 

 genus Perichcvta, which are not unfortunately thoroughly 

 well known anatomically, but in one instance, Perichceta 

 robusta from Mauritius, are probably distinct species. I 

 have described Perichceta mauritiana from the same 

 island, which is certainly not identical with any known 

 and adequately described species. There are thus some 

 facts to be drawn from this group of animals not 

 unfavourable to " Lemuria." 



But the most striking evidence perhaps is geological 

 and palseontological. This evidence I again abstract from 

 Mr Blanford's address to the Geological Society. It 

 comprises evidence derived from several distinct periods of 

 the Palaeozoic and Mesozoic epochs, and is therefore not 

 by any means so " fragmentary " as has been alleged. It 

 is pointed out that in carboniferous times there was a 

 great resemblance between the plant faunas of Australia, 

 India and South Africa. With this correspondence was~a 

 great difference from the flora of Europe. Supposing this 

 flora to have been transported across the sea, there would 

 of course be no use in invoking the presence of what Prof. 




182 MADAGASCAR FOSSILS AND " LEMURIA." [CH. Ill 



Suess terms " Gondwana land " instead of Lemuria. But 

 if so, why are there no European plants in the same strata 

 in India, &c. ? For such plants do occur in the carboni- 

 ferous strata of certain parts of Africa and Brazil. Nor 

 do we find this kind of evidence only in carboniferous 

 times. In the formation known as Cenomanian we have 

 similar evidence, though in this case derived from marine 

 organisms and thus serving to check the data derived 

 from plants. At Nerbudda, in Western India, eight species 

 of fossil Echinoderms have been found, of which six are 

 also known from European rocks. But in South India 

 26 species have been found, of which only four, and two 

 of these are doubtful, occur in European strata. The 

 inference obviously is that the Nerbudda fossils are the 

 remains of animals which lived in a sea continuous with 

 the sea of the same period in Europe, and that the 

 Trichinopoly beds are the bottom of a sea which was 

 separated from the northern sea by a land barrier. The 

 Trichinopoly fauna recurs in Natal. 



Further evidence of the same kind comes to hand from 

 a study of the Jurassic fauna of the world. Lastly, the 

 fossil Belemnites of Madagascar are not identical with 

 those of the beds of a corresponding age in Uitenhage, a 

 fact which may at first sight appear to be hardly worth 

 bringing forward in support of the present hypothesis. But 

 the interesting fact about these fossils is that they belong- 

 to forms which are typical dwellers in warm seas, while the 

 single Uitenhage Belemnite is as distinctively a cold-water 

 form, thus tending to prove the existence of a belt of land 

 shutting off a cold south sea from a warmer equatorial sea. 




CHAPTER IV. 



THE FAUNA OF ISLANDS. 



THE principles dealt with in the preceding Chapter 

 are also admirably illustrated by the fauna of islands, of 

 which some account will now be given. 



The Fauna of the British Isles. 



The islands of Great Britain and Ireland are situated 

 upon a bank which comes so near the surface that the sea 

 is nowhere more than comparatively a few fathoms deep. 

 From the neighbouring coast of France England is se- 

 parated by barely thirty miles. There can be no doubt 

 in fact that the separation is, geologically speaking, very 

 recent, probably within the period of human occupation. 

 We should expect therefore to find the very closest 

 similarity in the fauna of England of the adjacent parts 

 of the Continent ; this is precisely what we do find, the 

 differences being chiefly in the poverty of the British 

 fauna as compared with that of the Continent. 



As Mr Wallace has pointed out, this poverty is 

 probably to be accounted for by the recent glaciation of 




184' PECULIAR BRITISH BIRDS. [CH. IV 



these islands, which destroyed a large proportion of the 

 inhabitants, unable to escape to more southern and warmer 

 latitudes or, if they did, cut off from returning by the 

 severance of the land. Poor though the fauna is, there 

 are still a few species which are really peculiar to these 

 islands, and are not found, or at least have not as yet 

 been found, anywhere upon the Continent. As however 

 many of these supposed peculiar species are obscure and 

 small insects, it is quite within the bounds of possibility 

 that they remain to be discovered later upon the Continent, 

 Among the Vertebrata the peculiar species are mainly 

 fishes ; there are however three species of birds, or at 

 least forms that are reputed to be species, found nowhere 

 outside of the British isles ; the only one of these however 

 which is without any question at all a distinct form is the 

 grouse Lagopus scoticus. The Cole-tit Parus britannicus 

 is held by some naturalists to be distinct from the Parus 

 ater of the Continent ; and in the same way the 

 British form of the Long-tailed tit, called Parus rosea, is 

 distinguished from its ally in Europe. The St Kilda 

 wren is possibly also to be added to the list of peculiar 

 species. 



Mr Wallace enumerates no less than 15 different kinds 

 of fresh-water fishes which he states, on the authority of 

 Dr Gunther, to be well-marked species. They are entirely 

 Salmonoids and nearly all of them are lake fish ; they 

 include the familiar Gillaroo trout, the Loch Leven trout, 

 the Gwyniad, the Vendace and the Pollan. Considering 

 that in many cases these fishes are extremely restricted 

 in their range within the islands, it is not surprising that 




CH. IV] PECULIAR BRITISH INSECTS. 185 



they do not range beyond. The Welsh Chair for instance, 

 Salmo perisii, is limited to the Llanberris lakes. Out of 

 these fifteen fish no less than six are confined to Ireland. 

 The specialisation of these fish is comparable to that of 

 the Cassowaries and the Ibexes dealt with on another 

 page ; they live in isolated areas whose living inhabitants 

 can never intermingle except by the rarest circumstances, 

 such as a whirlwind taking up the young fry and depositing 

 them still alive in an adjacent lake ; at any rate the very 

 fact that they are of different species shows that inter- 

 communication is not frequent. 



The list of peculiar insects is a much longer one ; but 

 some entomologists hold that it is a list which is only at 

 present imposing upon paper; that in fact the insects 

 really await discovery upon the Continent. Mr Wallace 

 however is of opinion that the list of peculiar British 

 insects is in the main to be depended upon ; he points out 

 that all islands show an equal if not larger proportion of 

 peculiar insects than of any other class of animals. 

 Besides, the climate of this country is different from 

 that of any part of the Continent, a further reason for 

 the validity of the argument that there are really peculiar 

 species restricted to these islands. Of butterflies there 

 are only two species which are exclusively British ; and 

 both of these are very limited in their range within these 

 islands; indeed one has become in the last few years 

 absolutely extinct. This is the " Large Copper," Polyom- 

 matus dispar. Its extinction has been no doubt caused 

 by the draining of the fens where it was formerly abundant. 

 The other butterfly is a variety of one of the common 




186 MOLLUSCA OF IRELAND. [CH. IV 



" Blues " known to entomologists as Lyccvna ar/estis ; the 

 variety being termed L. artaxerxes ; it occurs upon 

 Arthur's Seat and upon some of the other Scottish hills. 



No less than 87 moths are given in Mr Wallace's 

 list as peculiar to Great Britain. Of these of course the 

 larger portion are " Microlepidoptera," and frequently 

 minute forms, which might be easily overlooked were they 

 really to occur also on the Continent. Though there are 

 these 87 moths they do not all of them rank as species. 

 However 61 are considered to merit specific distinction. 

 This number is, according to the late Mr Stainton, to be 

 further reduced to 50 undoubtedly distinct species since 

 some of the reputed species are rather local forms than 

 definable species. Of the beetles Mr Wallace's list shows 

 72 species and varieties confined to the British islands; 

 the list of insects concludes with the mention of three 

 Trichoptera, all apparently good species, which are not 

 found out of the British isles. 



The land and fresh water Mollusca present us with a 

 few peculiar forms ; a black slug spotted with yellow, 

 Geomalacus maculosus, was discovered on the shores of 

 lake Carogh in Kerry in the year 1842, and has not been 

 met with elsewhere since that year. A small pond snail, 

 Lymncva involuta, is confined to a small Alpine lake near 

 Killarney ; finally there are two small shells which are 

 ranked as species, one a bivalve, the other an univalve, 

 besides 79 varieties. 



The Rev H. Friend reports 1 the presence of a species 

 of Lumbricus (L. papillosas) in Ireland, which has not yet 



1 Irish Naturalist, Feb. 1894. 





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 LL 



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CH. IV] LEMURS. 187 



been found elsewhere, and Mr Benham's 1 peculiar new 

 genus Spargatiophilus, found in the Thames, is so far as 

 we know limited to that river. There are one or two 

 other examples of Oligochaeta which have not been met 

 with outside of the British islands. 



There are thus a fair number of animals which are 

 confined to the British islands ; but there are no marked 

 generic (except the worm Sparganophilus) or family types ; 

 nor is the proportion of peculiar forms large as compared 

 with that of the animals which are also found upon the 

 continent of Europe. But this is perfectly in harmony 

 with the geological history of these islands, which teaches 

 us that the severance from the continent of Europe is, 

 geologically speaking, an event of yesterday. 



The Fauna of Madagascar. 



Madagascar is a large island about twice the length of 

 England, and as broad nearly all through as the widest 

 part of England. It is situated about 250 miles from 

 Africa. It is largely forest covered ; but there are also in 

 the central granite plateau moors. The fauna is both 

 rich and peculiar. Among the Mammals the most 

 characteristic forms are the Lemurs. Of this group of 

 mammals there are no less than nine genera, viz. Indris, 

 Propithecus, Avahis, Hapalemar, Lepilemur, Lemur, 

 Cheirogaleus, Microcebus, and Ghiromys, absolutely con- 

 fined to the island. These genera contain all belonging 

 to the subfamilies Chiromyida?, Lemurinse, and Propi- 



1 Quart. Jonrn. Micr. Sci. Vol. xxxiv. 




188 RODENTS OF MADAGASCAR. [CH. IV 



thecinse ; the remaining Lemurs consist also of three 

 subfamilies, which however include but few genera and 

 species, and are distributed in Africa and in the Oriental 

 region. Doubtless, as Mr Lydekker has pointed out in 

 the " Royal Natural History," the excessive allowance of 

 Lemurs is partly to be attributed to the entire absence of 

 large and powerful carnivorous animals. Carnivora are 

 not at all abundant. But they include two highly 

 peculiar forms. Firstly, Cryptoprocta, a Viverrine believed 

 by some to have relations with the extinct Creodonta but 

 which is at any rate to be referred to a separate subfamily 

 of the Ailuroidea, and Eupleres, which is also an isolated 

 form and has some affinities to the Insectivora. This 

 latter group includes five genera of a peculiar family, the 

 Centetidse, found nowhere else in the world except in 

 certain islands of the West Indies l ; the Rodents, an 

 universally distributed family of mammals, all belong to 

 the Myomorpha (the rat tribe) ; but they are all peculiar 

 genera of that group, viz. Nesomys, Hallomys, Hypogeomys 

 and Br achy tar somys. The ungulates are exceedingly 

 poorly represented ; there is only a Potamochcerus (P. 

 edwardsi), and quite recently a Hippopotamus has been 

 dug up from marshes where its bones were commingled 

 with those of other living and recently extinct forms. Mr 

 Blanford 2 reckons that out of the twenty-four genera of 

 mammals of Madagascar only two, Potamochcerus and the 

 shrew Crocidura, exist in Africa. 



1 Mr Dobson however (Ami. and Mag. Nat. Hist. Sept. 1884) denies 

 that the W. Indian Solenodon is a member of this family. 



2 Presidential address to Greol. Soc. 1890. 




CH. IV] MESITES AND LEPTOSOMA. 189 



The birds are not so strikingly peculiar as are the 

 mammals ; still there are not a few genera and species which 

 are restricted to Madagascar. Among these is the re- 

 markable Mesites, which is believed to be allied to the 

 Sunbittern of tropical America and to the Kagu of New 

 Caledonia, and is possibly to be regarded as a relic of a 

 primitive group of rail-like birds once dominant in all 

 parts of the world. Leptosoma is also a peculiar bird, 

 whose affinities are far from clear. The late Mr W. 

 A. Forbes 1 thought from his investigations into its 

 structure that it might be regarded as the type of a 

 distinct family near to the Rollers (Coraciidae). The 

 Cuckoo genus Coua is also peculiar to the island, as are 

 also the Vasa parrot, Coracopsis, and a few more types. On 

 the whole the avian fauna is not so remarkable as the 

 mammalian ; but in both cases the fauna of Madagascar 

 stands out as noteworthy by the absence of animals which 

 might be expected to occur just as much as by reason of 

 the peculiar types which do occur. There is an entire 

 absence of the characteristic African Elephants, Rhino- 

 ceroses, Anthropoid Apes, Lions, Hyaenas, &c. and among 

 birds, of Hornbills, Plantaineaters, and Colies. 



The reptiles are almost as peculiar as the mammals. 

 The chief feature of the island is the presence of the 

 American genera Philodryas and Heterodon among snakes, 

 a fact which is remarkably paralleled by the Centetidae 

 among the Insectivora. There is an exactly analogous 

 case among lizards ; for two genera, Hoplurus, Chalarodon, 



1 P. Z. S. 1880. 




190 FERNANDO NORONHA. [CH. IV 



are Iguanoids a family otherwise restricted to America. 

 The Chamseleons are very abundant in Madagascar, more 

 so than in any other part of the world, though they are by 

 no means limited to the island. As with mammals and 

 birds the reptiles which are remarkable for their absence 

 are as numerous as those which are noteworthy for their 

 presence. The most striking example is perhaps the 

 large group of Monitor Lizards, which abound not only in 

 Africa but in many parts of the old world, to which 

 division of the globe they are confined. Some further 

 facts about the zoology of Madagascar will be found on 

 page 176 et seq., apropos of its relations to India. 



The Fauna of Fernando Noronha. 



The island of Fernando Noronha lies at a distance of 

 194 miles N.-E. from Cape San Roque on the coast of 

 Brazil. It consists now of an archipelago of small islands; 

 but the original discoverer, Amerigo Vespucci, speaks of 

 it as one island ; it seems probable therefore that the 

 splitting up into an archipelago has occurred within the 

 last 400 years. The recent formation of an archipelago is 

 also rendered probable by the fact that the individual 

 islets have not their peculiar inhabitants, but that in the 

 words of Mr Ridley *, whose report upon its zoology has 

 furnished me with the material for the present section 

 " almost all the species noted occur on all the islands 

 suitable for their existence." This is entirely different to 

 the older oceanic archipelagos, such as the Sandwich 



1 Trans. Linn. Soc. 1886. 




CH. IV] FAUNA OF FERNANDO NORONHA. 191 



Islands (see below). The fauna is poor. No indigenous 

 mammal is to be found, with the possible exception of a 

 mysterious rat belonging to a tribe which Vespucci 

 describes as " Mures quam maximi." This description 

 seems inapplicable to the black rat, which is now found in 

 company with the common mouse. The cat also is said 

 to have become feral, but there is not the slightest 

 ground for believing in a truly indigenous cat. There 

 appear to be only three land birds, of which two are 

 peculiar ; the peculiar species are Vireo gracilirostris and 

 Elainea ridleyana, both very nearly related to American 

 forms. The third bird is a dove, Zenaida maculata, 

 " merely a small race of the ordinary Z. maculata of the 

 South American continent." It is not, however, pecu- 

 liar even as a small race, to the islands ; for precisely 

 the same variation occurs in Brazil. 



Only three reptiles exist in Fernando Noronha. 

 These are an Amphisbcena (A. ridleyi) peculiar, a skink 

 (Mabuia punctata) from Demerara, and a common Gecko. 

 The peculiar species has its nearest ally in the West 

 Indies, not on the mainland of South America. 



The fresh-water Mollusca consist of a species of 

 Planorbis peculiar to the islands. The land Mollusca are 

 seven in number ; of these four are peculiar, but only as 

 species, not as genera. A peculiar Centipede is described 

 by Mr Pocock under the name of Geophilus ridleyi, whose 

 nearest ally occurs at San Francisco. There is also a 

 peculiar Millipede, Spirobolus noronhensis. Two species 

 already known were also met with. Among the Insects 

 are two peculiar genera, and a considerable number of 




192 AFFINITIES OF FAUNA. [CH. IV 



peculiar species. In all 75 species of Insecta were 

 identified, and out of these 27 were peculiar species, 

 including the two genera above referred to. The fresh 

 waters of the islands contained, besides the Planorbis 

 mentioned, an Ostracod and a Gammarus, both believed 

 to be peculiar. There was a total lack of fresh-water 

 fish and of fresh -water as well as terrestrial Amphibia. 



One earthworm is known from Fernando Noronha, 

 identified by Mr Benham with the widely ranging but 

 especially Neotropical Pontoscolex corethrurus. 



The most salient features therefore in the fauna of 

 these islands are the total want of mammals of an 

 indigenous character, of fresh-w r ater fish, and of Am- 

 phibians, the rarity of reptiles, and finally the large 

 number, speaking relatively to the total of course, of 

 indigenous forms peculiar to the island. Of these how- 

 ever but few are of new generic types ; but this statement 

 as in the case of the fauna of Kerguelen, to be dealt 

 with presently, must be tempered by reflection as to the 

 different ideas which different naturalists have of the 

 value of a genus. As to the affinities of the fauna it is 

 noteworthy that the West Indies enters largely into the 

 matter ; there is not, as might be assumed at first, an 

 absolute likeness with the nearest coasts of South America. 

 But the winged fauna, Mr Ridley points out, whether 

 they are endemic or have a wider distribution, have a 

 South American facies which is quite unmistakable. 




CH. IV] BIRDS OF KERGUELEX. 193 



The Fauna of Kerguelen. 



The island of Kerguelen is situated in the southern 

 ocean in lat. 50, about half way between Australia and 

 the Cape of Good Hope. It is a large island of irregularly 

 indented form measuring in greatest diameter some 80 

 miles. The island is moreover situated on a plateau 

 which extends for a distance of more than 150 miles. 



The island is entirely built up of volcanic rocks ; it is 

 chiefly formed of basalt ; but trachyte and phonolite enter 

 also into its composition. 



Our information as to the fauna of Kerguelen is 

 apparently fairly complete. It was investigated by an 

 English expedition some years ago, the results of whose 

 discoveries were published by the Royal Society in 1875. 

 Later the " Challenger " stayed for some time at various 

 parts of the coast, and the German ship " Gazelle '" during 

 its voyage in the years 1874 76 touched at the island 

 and collected a quantity of material. 



In spite of the large size of the island, there is no 

 indigenous mammal ; the only mammal indeed which 

 occurs there, apart of course from marine forms, is the 

 ubiquitous Mus musculus. As the island is visited by 

 whale fishermen it is easy to understand how the common 

 mouse may have been introduced in ships. The only 

 land bird is the duck, Querquedula eatoni, a species 

 peculiar to this island and to the not very remote Crozets ; 

 the bird lives in marshes. Of the marine birds Sterna 

 virgata is also peculiar to Kerguelen and to the Crozets. 



B. Z. 13 




194 INSECTS OF KERGUELEN. [CH. IV 



Ooly a single species of land shell has been so far 

 discovered ; this is Patula hookeri, a species closely allied 

 to Helix diance of S. Helena, to H. quadrata of Juan 

 Fernandez and to H. tessellata. 



Among insects there are on the other hand several 

 peculiar forms. The beetles are in every case without the 

 second pair of wings ; they comprise Ectemnorhinus viridis 

 and a few other species of that genus, Phytosus atriceps 

 and Cannonopsis. A moth with rudimentary wings has 

 been recorded, as well as the peculiar genus (peculiar to 

 the island) Embryonopsis halticella. The Diptera do not 

 show the same rudimentary character of the wings that is 

 met with among the Coleoptera; there are however six 

 peculiar genera with a species apiece and an introduced 

 form. 



The spiders of the island are represented by two 

 peculiar genera, Myro and Poecilophycis, of which the 

 latter is so aberrant that the Rev. O. Pickard-Cambridge 

 has felt it necessary to form an entirely new family for its 

 reception. Among the fresh-water invertebrates, which 

 are not very numerous, there are no peculiar genera; but 

 all the species are, so far as we know at present, peculiar ; 

 these comprise species of the two Crustacean groups 

 Cladocera and Copepoda, and an Enchytra3id (unidenti- 

 fied). One terrestrial Annelid has been found and 

 described by Lankester as an Acanthodrilus 1 (A. Tcergue- 

 lenensis) ; this is a species peculiar to the island, unless 

 the Acantliodrilus of the Crozets be the same ; but the 



1 Phil. Trans. Vol. 168, Extra Volume. 




CH. IV] KERGUELEN AND THE GALAPAGOS. 195 



genus is widely spread in the antarctic region of the 

 globe l . 



There are five striking points about the fauna of 

 Kerguelen which may be emphasised. In the first place 

 of course, the poverty of the fauna. Secondly, the immense 

 number (relatively speaking) of peculiar genera ; thirdly, 

 the fact that there is only one terrestrial species (exclud- 

 ing birds) which is not peculiar to the island; and fourthly, 

 that the fresh-water species are not so peculiar as the 

 purely terrestrial. The fact that the Coleoptera are 

 without the second pair of wings the pair which are 

 used for flying in the normal Coleoptera and that there 

 is a moth with rudimentary wings, completes the more 

 remarkable facts which characterise the indigenous in- 

 habitants of Kerguelen. 



The Fauna of the Galapagos. 



The Galapagos are a group of sixteen islands, five 

 larger and eleven small islands situated to the west of 

 the South American continent, about 600 miles from the 

 coast of Ecuador. They have been explored more than 

 once with a view to their fauna. The most recent account 

 of them is from the pen of Dr Baur 2 , who made a careful 

 study of the entire fauna. 



As is the case with Kerguelen, the rocks of which the 

 Galapagos are built up are entirely volcanic ; they consist 

 of basaltic rocks, masses of scoriae, and lavas ; but there 



1 See p. 60. ~ American Naturalist, 1892. 



132 




196 REPTILES OF THE GALAPAGOS. [CH. IV 



are also, on Charles Island, remains of older volcanic 

 formations, which recur in one or two of the smaller 

 islands. All the islands of the archipelago are placed 

 within the 1000 fathom line. They were first discovered 

 in the sixteenth century. 



Mammalian life is not entirely wanting, but it is 

 scarce, in these islands. At present we are only acquaint- 

 ed with two species ; one of these is a mouse belonging 

 to the American genus Hesperomys, which may or may 

 not be indigenous. The other mammal is a bat ; but our 

 knowledge is here not accurate ; for the bat has been only 

 seen and not collected. 



There are on the other hand a good many reptiles. 

 The most famous are of course the huge tortoises, which 

 have given their name to the archipelago ; there is no 

 doubt that these bulky creatures, which sometimes reach 

 a weight of 700 pounds, are truly indigenous; for they 

 were seen by the Spaniards who discovered the islands. 

 The peculiar thing about these tortoises is that different 

 islands are characterised by different species. There are 

 in all six species of these Chelonians, but the exact 

 locality of one or two is not known. 



Tortoises however are not the only reptiles which live 

 in or round these islands. Four genera of Lizards exist 

 there ; these are Tropidurus, Conolophus, Amblyrhynchus, 

 and the Gecko Phyllodactylus. 



Of the genus Tropidurus there are altogether eight 

 species on the islands, each island as in the case of the 

 tortoises having its own peculiar form. Amblyrhynchus is 

 a marine genus feeding on seaweeds ; it is like the last a 




CH. IV] BIRDS OF THE GALAPAGOS. 197 



member of the Iguanidae, a family of lizards just not 

 absolutely confined to the New World. Dr Baur thinks 

 that when the species of Aniblyrliynclius come to be 

 examined critically, differences will be found like those 

 between the tortoises of the different islands. There are 

 three geckos on the islands, all belonging to the genus 

 PhyllodactyluSj already mentioned. These are P. galapa- 

 yoensis, P. leei, and P. tuber cidos its ; the last lizard is the 

 only species found on the islands which is not peculiar to 

 them. In addition to these lizards there are two snakes ; 

 they are both very closely allied to South American 

 forms. 



The land birds, according to Mr Salvin's paper upon 

 the subject 1 , are in all 31 species. Of these only one, 

 the Rice bird, is not peculiar to the islands. As Mr 

 Wallace has pointed out there is every possible transition 

 between this case and birds which are so different from 

 any found upon the adjacent mainland that they are not 

 merely of different genera, but of very dubious affinities. 

 The birds belong altogether to fourteen genera, of which 

 four are peculiar to the Galapagos ; these peculiar genera 

 are Certhidea, one of the Sugar birds (Coerebida3), Geospiza, 

 Cactornis and Camarhynclius, all of them Fringillida?. 

 The birds that are merely of different species are all allied 

 to South American or West Indian forms, or of course to 

 forms which like Stria flammeci (the common Barn Owl) 

 are of universal range. 



As with the reptiles certain of the peculiar birds are 

 confined to a single island ; the same genus has one 



1 Trans. Zool Soc. 1875. 




198 INSECTS OF THE GALAPAGOS. [CH. IV 



species in one island and one in another. Thus Mimus 

 parvulus is only met with in Albemarle Island and Mimus 

 trifasciatus only in Charles Island. 



The insects of these islands are not very numerous. 

 Mr Wallace following Mr Waterhouse allows about 

 35 species of Beetles, belonging to 2.9 genera. The 

 species are as a rule peculiar and so are the genera in 

 some cases. But as they are " mostly small and obscure 

 insects," it is difficult to be positive upon either of these 

 points. 



The Orthoptera of the Galapagos are equally interest- 

 ing. Considering that nine different expeditions have been 

 made to these islands, from which insects of this group 

 have been brought back to Europe or America, and 

 reported upon, it may be fairly assumed that our know- 

 ledge of the fauna is not too incomplete to permit of 

 conclusions. There are in all 20 species, of which Dr 

 Scudder, the latest writer on the subject 1 , leaves with 

 justice five out of consideration, as they are world- wide 

 forms and probably not endemic. The remaining 15 

 include five distinct generic types ; but the whole assem- 

 blage presents, according to Dr Scudder, a South and 

 Central American facies. Another matter worthy of 

 mention is the very great prevalence of apterous or 

 sub-apterous species. The 20 species are in many cases 

 confined to one of the islands of the Galapagian archi- 

 pelago. This is so with no less than eleven of them. A 

 few are found in two or three of the islands ; one species 

 Schistocerca melanocerca is unique for its wide dis- 



1 Bull. Mus. Comp. Zool. Harvard, 1894. 




CH. IV] PHYSICAL FEATURES OF NEW ZEALAND. 199 



tribution in the archipelago ; it occurs in no less than 

 eight islands. The specimens were submitted to a rigid 

 scrutiny to discover whether they could be referred to 

 distinct races, but the most that can be said apparently is 

 that " there is a distinct tendency toward the formation of 

 races." On the other hand another species of the same 

 genus S. literosa which occurs in three islands, can be 

 separated into as many races. 



The Fauna of New Zealand. 



The fauna of New Zealand has been so abundantly 

 investigated through the labours of Capt. Hutton and 

 others, that it is one of the best known quarters of the 

 globe. 



It will be well to preface our account of this fauna by 

 a brief sketch of the physical features of the island and 

 the surrounding ocean. The name New Zealand is 

 applied to two principal islands which are together 

 " about as large as the kingdom of Italy." Their climate 

 is mild and equable, while the vegetation is luxuriant and 

 there are no deserts such as occur in Australia. The two 

 islands lie upon an extensive plateau, where the water is 

 not more than 1000 fathoms deep ; a prolongation of this 

 submarine plateau runs out and joins New Caledonia to 

 the north, whence it is continued on to the Australian 

 continent ; another spur runs out so as to embrace Lord 

 Howe Island ; elsewhere a depth of over 2000 fathoms 

 divides New Zealand from Australia. Its distance from 

 Australia is about 1200 miles. The geological structure 




200 BIRDS OF NEW ZEALAND. [CH. IV 



of the islands shows deposits of ancient sedimentary rocks, 

 besides Jurassic, cretaceous, and tertiary strata; it is thus 

 evidently a continental island, though it exhibits much 

 volcanic material of ancient as well as of more modern 

 date. 



The fauna of New Zealand is highly remarkable ; 

 though the island is of the continental type there are 

 hardly any mammals, no large mammals at all ; only two 

 bats and a rat the latter being almost certainly an im- 

 portation are known to exist in New Zealand. Rumours 

 of a larger and, conjecturally, a carnivorous mammal have 

 been from time to time floated ; but the domestic cat may 

 be responsible for the footprints, assigned to a new and 

 isolated type of New Zealand mammal. The bats however 

 are not of universally distributed species ; one of them is 

 an Australian form, Scotophilus tuberculatus ; the other is 

 a peculiar genus, Mystacina tuberculata. The birds are 

 very characteristic ; the most salient type is of course the 

 but recently extinct Dinornis and its allies ; there were 

 until well within the historic period a large number of 

 species of Dinornithidse. The existence or at any rate 

 the abundance of these often huge birds is ascribed to the 

 absence of mammals of carnivorous mammals that is to 

 say. The curious genus Apteryx is found in New Zealand 

 and nowhere else; of this genus there are about four 

 species. It is regarded by Fiirbringer as allied to the 

 Rails, but to be a low stock of the Ralline birds, a little 

 more modified however than the Cassowaries, Emus and 

 the rest of the so-called Struthious birds ; the Apteryges 

 are placed by the same author in close proximity to the 




CH. IV] BIRDS AND REPTILES OF NEW ZEALAND. 201 



Dinornithidse. It is not only these archaic forms of birds 

 which are peculiar to New Zealand. Nor are they the 

 only flightless birds that inhabit this country. The 

 parrot, Stringops, an undoubtedly ancient form of parrot, 

 is a very characteristic inhabitant ; so too are the rails, 

 Ocydromus and Notornis ; all these birds, though with 

 wings better developed than those of the Apteryx, or 

 Dinornis, are practically without the power of flight. 

 The " Parson-bird," Prosthemadera, is another peculiar 

 form. Mr W. A. Forbes has described 1 as peculiar 

 Mesomyodian genera of Passerine birds, the genera Xeni- 

 cus and Acanthisitta. He regards them as worthy of 

 inclusion in a separate family, to which the name Xeni- 

 cidce is applied ; the only other family of Mesomyodian 

 Passeres that enters the Australian region is that of the 

 Pittidas. The Xenicicbe are also allied to the Tyrannidie 

 and to the Cotingidas of the New World. Another re- 

 markable Passerine of New Zealand is Heteralocha, which, 

 like the equally restricted Callceas and Creadion, is 

 referable to the family Sturnidas. Among reptiles the 

 isolated Hatteria is the most remarkable ; the Amphibia 

 are represented by a single frog, Liopelma hochstetteri 

 allied to European forms belonging in fact to the Palae- 

 arctic family Discoglossidaa. It is curious that there are 

 no scorpions in New Zealand 2 , since that family exists in 

 Australia. The earthworms of this part of the world are 

 mainly Acanthodrilida3, including three genera confined to 



1 P. z. s. 1882. 



2 Pocock. On the Geographical Distribution of Scorpions. Natural 

 Science, 1894. 




202 EXTINCT BIRDS OF NEW ZEALAND. [CH. IV 



New Zealand. The characteristic Australian types are 

 either absent or but feebly represented. The South 

 American genus Microscolex is represented by six distinct 

 species. 



In Mr Lydekker's recently issued " Catalogue of the 

 Fossil Birds " in the British Museum is an exhaustive list 

 of the extinct flightless or wingless birds of New Zealand, 

 which were wonderfully numerous ; they may be fairly 

 considered as part of the existing fauna of the island, 

 since they have been in existence there up to the historic 

 period, or disappeared from the island at a period only 

 just antecedent to it. A new genus, Pseudapterya, with 

 but a single species, represents a bird hardly different 

 from Apteryx and of about the size of the comparatively 

 small Apteryx oweni. Of Dinornis itself no less than four 

 species are allowed, many of those formerly referred to 

 the genus being now better placed in closely related but 

 different genera. These are Megalapteryx, Anomalopteryx, 

 Emeus, Pacliyornis, with at any rate 17 species between 

 them. Another very remarkable and characteristic inhabi- 

 tant of New Zealand is the large goose, Cnemiornis, which 

 is regarded as a near relative of the Australian Cereopsis ; 

 it was a bird with apparently no powers of flight, for the 

 keel of the sternum, as in the Struthious birds, is aborted. 

 The bird was considerably larger than the existing 

 Cereopsis. There is one certainly known species of the 

 genus, Cnemiornis calcitrans, and one doubtful one, to 

 which Mr Lydekker does not give a name. A large rail, 

 Aptornis, is another inhabitant of New Zealand whose 

 remains, belonging to two species, are found associated 




CH. IV] FAUNA OF SANDWICH ISLANDS. 203 



with those of the Dinornis. Though these great birds 

 must have led a comparatively unharassed life in New 

 Zealand before the advent of the Maories, who are 

 probably chiefly responsible for their disappearance, there 

 were in the islands at the same time great birds of prey, 

 which might have proved able to destroy the largest 

 of Dinornithidse. These were birds now referred to the 

 genus Harpagornis, half again as large as the Golden 

 Eagle. They are believed to be most nearly allied to the 

 genus Aquila, but by some are placed rather in the 

 neighbourhood of the Kites or Falcons. As all the last 

 mentioned birds come very near to each other, the 

 affinities of the Harpagornis may be considered to be well 

 known. 



Fauna of the Sandwich Islands. 



Our information about this group of islands is growing 

 rapidly. The second edition of Mr Wallace's Island 

 Life contains a great deal more information than the 

 first edition ; and since that book was published a 

 Committee appointed to take steps for the exploration 

 of the islands have reported briefly to the British Asso- 

 ciation 1 . The islands in question are a group of largish 

 islands, 2,350 miles from the coast of America and purely 

 volcanic in structure. They have of course no indigenous 

 mammals ; there is a reptile or two ; but the birds are the 

 most remarkable and interesting. Dr Sharp states that 

 out of 78 birds found in the islands 57 are peculiar. 

 Seven or eight of the twelve or fourteen peculiar genera 



1 Rep. Brit. Assoc., 1893, p. 783. 




204 BIRDS OF SANDWICH ISLANDS. [CH. IV 



belong to a family Drepanididse, which is absolutely 

 confined to these islands and which may have, thinks 

 Mr Wallace, affinities on the one hand to the Oriental 

 Dicceidse and on the other to the characteristic American 

 family of Vireonida3, or Greenlet. The Passerine birds of 

 the islands are the most interesting, for two reasons; firstly 

 they comprise nearly all the peculiar genera of the islands, 

 and secondly they show a remarkable specialisation among 

 the islands. The genus Loxops, for example, of the Dre- 

 panididse has a different species in each of the islands 

 Hawai, Molokai and Mani 1 . This specialisation into pecu- 

 liar genera, and species with so restricted a range, is of 

 course correlated with the immense distance to be traversed 

 and the feeble flight of these birds when compared with 

 that of say the ducks and geese. There are however pecu- 

 liar genera among the non-Passerine birds, as the little 

 flightless Rail Pennula ecaudata. Among other peculiar 

 birds are the Sandwich Island goose, Bernicla sandvicensis, 

 and a peculiar Buzzard, Buteo solitarius. Of land and 

 fresh-water Mollusca Dr Sharp states that there are 475 

 species, all of them peculiar. Out of 1000 insects 700 are 

 peculiar ; but Dr Sharp thinks that the numbers are very 

 much less than the total will ultimately prove. 



General Observations upon the Fauna of Islands. 



We have now dealt at some length with the fauna of 

 six islands or groups of islands. A consideration of the 



1 Wilson, Aves Hawaiensis, and Rothschild, The Avifauna of Laysan. 




CH. IV] COMPARISON OF ISLANDS. 205 



facts brought forward will at once serve to divide these 

 islands into at least two groups, which are again capable 

 of subdivision. 



Continental Islands. 



In the first category are Great Britain and Madagas- 

 car, which have a copious indigenous fauna of mammalia 

 and amphibia ; to the second category belong the other 

 islands, which have either no mammalia at all or they are 

 extremely few, at most one or two species identical with 

 those found upon the adjacent mainland, and which are 

 absolutely destitute of amphibia of any kind. 



These distributional facts go hand in hand with Geo- 

 logical structure. Great Britain and Madagascar are 

 detached portions of continents, which have been sepa- 

 rated from the mainland for varying periods. The re- 

 maining islands, with the possible exception of the 

 Galapagos, which will be considered later, are not such 

 fragments but have arisen de novo in the ocean by 

 volcanic agency. They have never had any connection 

 with any continent. The relation between the geo- 

 logical structure and the nature of the inhabitants is a 

 real one ; the mammalia, as has been already observed, 

 are not capable of extended migration over the sea on 

 their own account ; it could only be but rarely that a 

 mammal could reach a distant and oceanic island ; and it 

 would be necessary in many cases that two individuals at 

 least should emigrate within a reasonable time of each 

 other. The immense tract of ocean which separates 

 Kerguelen from the nearest continent has proved an 




206 GREAT BRITAIN AND MADAGASCAR. [CH. IV 



impassable barrier to mammalian life ; for the common 

 mouse, which, as has been said, occurs there, could easily 

 be, and doubtless has been, conveyed there by man's 

 agency. With the Amphibia the difficulties are even 

 greater; for in their case there is not only the diffi- 

 culty of transport, but the serious additional difficulty 

 that sea-water is fatal to them. It might be urged that 

 as some of these purely oceanic islands are of large 

 dimensions and have probably been larger, mammalian 

 life might have come into existence upon them independ- 

 ently. This assumption however would be entirely 

 contrary to our ideas of evolution; indeed it is not 

 necessary to argue from any a priori point of view, for we 

 are confronted with the fact that some oceanic islands at 

 any rate e.g. S. Helena are not incapable of supporting 

 mammalian life, for imported animals do well, and yet 

 they are totally without an indigenous fauna of the kind. 

 On the other hand, there is no doubt at all that both 

 Great Britain and Madagascar are severed portions of 

 continents, which were amply stocked with mammalian 

 life when they were finally cut adrift. 



Although there is this general similarity between the 

 two islands just mentioned, it is clear that there are also 

 differences, and considerable differences too. The mam- 

 malian fauna of Great Britain, and for the matter of that 

 the fauna in general, is poor in peculiar forms, restricted 

 to the archipelago and not found living in the continent 

 of Europe ; there are a good many peculiar species, it 

 is true, but very few in comparison to the fauna as a 

 whole. 




CH. IV] KERGUELEN AND FERNANDO NORONHA. 207 



On the other hand, Madagascar abounds in peculiar 

 forms, even of family rank, and certainly in numerous 

 cases of generic rank. This difference again is correlated 

 with physical conditions. Britain is separated from 

 France by scarcely 30 miles of sea, which is so shallow 

 that, as is stated, the dome of S. Paul's Cathedral in 

 London, if submerged anywhere in that sea, would stand 

 for the most part clear above the waves. On the other 

 hand Madagascar lies 250 miles from the African coast, 

 from which it is separated by an ocean varying in depth 

 from 1,000 to 1,500 fathoms. The inference is that the 

 separation between Britain and Europe is of much later 

 date than that between Madagascar and Africa. More 

 time would in all probability elapse between the scooping 

 out of the deep channel which divides Madagascar from 

 Africa, than of the narrow and shallow Straits of Dover. 



Oceanic Islands. 



The four oceanic islands again possess faunas which are 

 not absolutely the same in character. Fernando Noronha 

 and Kerguelen contrast with the Galapagos and the 

 Sandwich Islands by reason of the poverty of their fauna. 

 They differ from each other also. Kerguelen has a poor 

 fauna, hardly if at all richer than that which populates 

 Fernando Noronha, but the number of peculiar types is 

 larger and more marked ; more marked because the types 

 are to a considerable extent of peculiar genera. This would 

 tend to prove that Kerguelen is older as an island than is 

 Fernando Noronha ; more time has elapsed since it was 




208 THE GALAPAGOS. [CH. IV 



originally populated, and during that time the descendants 

 of the original migrants have had time to pursue an 

 independent line of development. That Kerguelen is an 

 island of some antiquity is shown by the submerged bank 

 which surrounds it, which would have demanded time for 

 its submergence, and by the occurrence of stratified, 

 though originally volcanically produced, rocks. We now 

 come to the remarkable case of the Galapagos. Reptiles 

 are often not totally wanting in islands of purely oceanic 

 type ; there seems to be some method, at present mys- 

 terious, in which reptiles have the advantage over 

 mammals in traversing the sea. So that the actual 

 presence of lizards and snakes, though they are rather 

 numerous, is not an absolute bar to regarding the 

 Galapagos as of purely oceanic origin. The great tortoises 

 seem to be a huge difficulty ; there is no way of slipping 

 out of the problem by bringing in the help of settlers ; 

 besides, in another island, Aldabra, there are also huge 

 tortoises. This island belongs to the Comoro group lying 

 at some distance from Madagascar but connected with it 

 by a shallow of about 1,000 fathoms in depth. There is 

 much the same relation between Aldabra and Madagascar 

 that there is between the Galapagos and the South 

 American continent. But in neither case could these 

 huge tortoises, sometimes weighing 700 pounds, have 

 swum across a wide and deep ocean. And the fact that 

 the first visitors to the Galapagos mention them shows 

 that they have not been introduced by man. 



Dr Baur thinks that these tortoises are of themselves 

 almost sufficient to prove the former connection of the 




H. IV] ORIGIN OF GALAPAGOS. 209 



Galapagos with the mainland. A further argument in 

 the same direction is offered by the fact that the fauna of 

 the mountain peaks of the Galapagos at a height of 900 

 feet are like that of the mainland at 9000 feet. Given a 

 great depression this would be accounted for. That view 

 of the matter clears up in a satisfactory way the difficulty 

 of the tortoises ; it would be inferred from this way of 

 looking at the problem that the huge Chelonians of the 

 Galapagos like those of Aldabra had been able to hold 

 their own by isolation and consequent freedom from 

 competition or persecution. Mr Wallace however is of 

 opinion that this assumption is unnecessary. " Con- 

 sidering the well-known tenacity of life of these animals," 

 he remarks, " and the large number of allied forms which 

 have aquatic or subaquatic habits, it is not a very 

 extravagant supposition that some ancestral form carried 

 out to sea by a flood was once or twice safely drifted as 

 far as the Galapagos, and thus originated the races which 

 now inhabit them." The almost total disappearance of 

 mammals requires explanation on the hypothesis that the 

 Galapagos are a disjointed piece of South America. 



The study of the distribution of animals thus throws an 

 important light upon geological problems, and tends to 

 support the belief that animal life has come into being 

 upon large continental tracts and that it is liable to 

 variation when isolation is brought to bear. A careful 

 comparison of island fauna moreover enables some esti- 

 mate, chiefly of course comparative, to be made concerning 

 the age of the island in question. 



B. Z. 14 




210 NEW ZEALAND. [CH. IV 



Anomalous islands. 



New Zealand is spoken of by Mr Wallace with justice 

 as an "anomalous' 2 island. Though continental it has 

 many of the characters of an oceanic island which has 

 never had any connection with a continent. It contrasts 

 in the most marked way with Madagascar. Unless the 

 mysterious carnivore already referred to really turns out 

 to be what has been suggested, a kind of otter, New 

 Zealand possesses no indigenous mammals except the 

 flying bats, which are largely uninfluenced by the ordinary 

 barriers to mammalian dispersal. The " Maori rat " may 

 be slightly different from the Mus rattus; but the 

 difference, if present, is not considerable. On the other 

 hand there is one frog, and frogs are absent from truly 

 oceanic islands. Most remarkable are the birds of New 

 Zealand and the unique Hatteria, the representative of 

 an otherwise extinct group of Saurians. The fact that 

 the majority of the birds are flightless is due perhaps 

 to the absence of destructive mammalia ; this flightless- 

 ness applies not only to the Apteryx and the Dinorni- 

 thida?, but in a lesser degree to the but recently extinct 

 Cnemiornis and to the Rails. The islands are perhaps 

 too large to permit of a comparison between this in- 

 capacity for flight on the part of the birds of New 

 Zealand and the defective wings of the Coleoptera of 

 oceanic islands generally. Before considering the bear- 

 ings of these facts upon former land connections, if any, 

 between New Zealand and the most adjacent regions, it is 

 convenient to refer to an ingenious suggestion on the 




CH. IV] CASSOWARIES AND MOAS. 211 



part of Captain Hutton as explanatory of the Moas of 

 New Zealand. These recently vanished birds are re- 

 presented by a large number of different species which 

 are now placed in more than one genus. The area upon 

 which they lived is small, and accordingly the number of 

 species is rather remarkable. In the Australian region 

 there are nearly as many Cassowaries as there are Moas. 

 Now these Cassowaries are spread over a considerable 

 number of islands; they are not limited to the con- 

 tinent of Australia but occur also in Ceram, New 

 Britain, New Ireland, &c. On these various islands and 

 continent are different species. This suggests that 

 isolation and the absence of opportunity for retaining the 

 type by crossing with the parent stock was responsible 

 for the great variety of Cassowaries. If New Zealand 

 had been at one time a mass of not very distantly 

 separated islands, each inhabited by its own particular 

 species of Moa, a state of affairs very like that now 

 existing among the islands lying to the north of Australia 

 would result ; this is precisely what Mr Hutton in effect 

 suggests. Mr Wallace regards the suggestion as a rea- 

 sonable one, and it is impossible to follow a better opinion. 

 If there has been this oscillation of New Zealand, whereby 

 a continent (comparatively speaking) has been broken up 

 into an archipelago, and reconstructed into a continent 

 again, it may be that we have a clue to the existence of 

 the large, clumsy, and flightless birds such as the 

 Cnemiornis and the Notornis. Their case might well be 

 analogous to that of the Galapagan and Aldabran tort- 

 oises ; or perhaps also to that of the flightless beetles of 



142 




212 RELATIONS OF AUSTRALIA AND NEW ZEALAND. [CH. IV 



the Azores. At the same time if the tract of land, 

 now known a"s New Zealand, were a mass of smallish 

 islands during the time that mammalian life came into 

 existence upon the Australian continent, the small 

 superficies of the individual islands might hinder the 

 successful immigration of the primitive mammalia ; to get 

 a successful footing would be in every way more likely 

 upon a larger than upon a smaller land surface. The 

 chances of landing too would obviously be greater in 

 proportion to the extent of coast line. Had New Zealand 

 been as Madagascar undoubtedly was, a broken-off frag- 

 ment of a formerly more extensive Australian continent, 

 there would surely be some traces of at least marsupial 

 life. On the other hand it might be well urged in reply 

 to this that the connection of the two countries may have 

 antedated the advent of marsupials. A separation may 

 have occurred while Australia was only populated by the 

 lower vertebrates. Or with equal probability it might be 

 pointed out that Australia was joined with New Zealand 

 when it was itself divided into two halves, of which the 

 western had only just received its stock of marsupials. 

 This latter is Mr Wallace's view. There is no doubt that 

 the fauna of New Zealand is one of the greatest puzzles 

 that distribution has to offer. 



Some peculiarities of island animals. 



Having already dealt with peculiarities of island faunas 

 as regards the classes of animals which inhabit them, the 

 absence of some kinds of animals and the presence of 




CH. IV] FLIGHTLESS BIRDS OF ISLANDS. 213 



others, there remains another series of facts of which a 

 brief epitome may be useful. It has been already pointed 

 out incidentally that many islands, whether oceanic or 

 not, are, or were until well within the historic period, 

 inhabited by birds not only of large size but also without 

 the power of flight, either owing to the partial abortion 

 of the wing muscles and bones or simply by use, like 

 the Weka rail of New Zealand. This is quite a common 

 characteristic of the birds of islands. The Dinornis of 

 New Zealand, the Dodo of Mauritius, the " Solitaire " of 

 Rodriguez, are instances to the point. It seems highly 

 probable that this large size coupled with an incapacity 

 for flight was correlated with the absence or at least the 

 rarity of fierce enemies ; mammalia are, if not absent, 

 small in those islands where these large and flightless 

 birds exist or existed. It is to be observed that even 

 among the Struthious birds, all of which are flightless, the 

 majority of the species are inhabitants of islands. This 

 majority is mainly formed it is true by the genera of 

 Dinornithida? ; but a large number of Cassowaries are 

 exclusively island forms. 



Birds are not the only animals which grow to a large 

 size upon islands. On a former page attention was called 

 to the huge tortoises of the Galapagos. These tortoises 

 are not altered apparently in any other respect ; they do 

 not for instance show any structural feature which could 

 be said to be analogous to the Sightlessness of so many of 

 the ornithic inhabitants of islands. But the tortoises of 

 the islands are actually the largest of the whole tribe ; 

 their unwieldy bulk, likely to be disadvantageous where 




214 GIANT TORTOISES. [CH. IV 



the struggle for existence was keener, is in all probability 

 to be referred to the same causes as the defenceless state 

 of the Dodo and other island birds. 



The island of Mauritius was also inhabited quite 

 recently by gigantic tortoises which are now without 

 exception extinct. Dr Gadow in a recent communication 

 upon the subject 1 distinguishes no less than six "forms' 5 

 of these. He uses the word " form ' because it seems 

 improbable that they have the full value of species ; and 

 yet names are given to them without any such prefix as 

 "forma " or " var" It is at least not usual for species of 

 the same genus and all these giants belong to Testudo, 

 just like those of the Galapagos to herd together in a 

 limited tract. Now five out of these six forms have 

 deposited their bones in one marsh ; so much confused 

 were they, owing no doubt partly to the fault of those 

 who fished them out, that in some cases the bones seem 

 to have entirely lost their mutual relations. Waiving 

 the question of species it is clear that great variability 

 reigned among these large and unpersecuted inhabitants 

 of the Mauritius their freedom from enemies being also 

 perhaps indicated by the thinness of the shells. It is 

 incorrect to make the general statement that great size is 

 characteristic of island tortoises only, because the giant 

 Colossochelys of India and some other forms flourished 

 under continental conditions. But among living or but 

 recently extinct tortoises large size seems to have been 

 only attainable on these favoured because restricted spots, 



1 Trans. Zool. Soc. Vol. xm. 




CH. IV] BATS OF NEW ZEALAND. 215 



where natural selection imposed no check upon unwieldy 

 bulk. 



Dr Dobson has pointed out the curious circumstance 

 that bats are not nearly so numerous in oceanic islands as 

 birds. From many considerations they ought to be ; 

 their nocturnal habits and the general nature of their 

 insect food are characters which would favour successful 

 colonisation. The reason apparently for their comparative 

 scarcity in islands which must have been stocked with 

 them from the nearest mainland is correlated with the 

 comparative rarity of flying objects. On another page 

 I direct attention to the fact that the insects of oceanic 

 islands are largely like the birds flightless. Now bats are 

 as a rule thoroughly aerial in their habits ; they seek their 

 prey upon the wing. This fact, thinks Dr Dobson, is 

 largely responsible for the poverty of Xew Zealand in 

 Chiroptera. 



Even in the British islands poor though their fauna 

 is there are eight times as many bats as in New Zealand. 

 One of the peculiar New Zealand bats, Mystacina tuber- 

 culata, "has the claws of the pollex and toes remarkably 

 elongated, very acutely pointed, and provided at the base 

 of each with a small talon projecting from its concave 

 surface near the base ; the wings are peculiarly folded so 

 as to occupy the least possible space ; and they and the 

 interfemoral membranes are preserved from injury by 

 being encased, when so folded, in a specially thickened 

 part of the wing and interfemoral membrane, analogous to 

 the thickened part of the anterior wings in Hemiptera, 



1 Ann. Mag. Nat. Hist. Sept. 1884. 




216 ISLAND INSECTS. [CH. IV 



and to the elytra of the Coleoptera ; furthermore the 

 plantar surface of the foot including the toes is covered 

 with very soft and very lax integumental tissue deeply 

 wrinkled." These peculiarities of structure, thinks Dr 

 Dobson, must have some relation to the habits of the bat. 

 The probability seems to be that the structure of the feet 

 gives to the animal an unusual power of grasping tightly 

 any rough surface like the bark of a tree, while the wings 

 not being needed when the creature is in such a situation 

 are protected from injury by being carefully stowed away 

 in the fashion described. Dr Dobson is of opinion that 

 this bat instead of hunting its prey on the wing seeks it 

 upon the trunks and branches of trees up and along 

 which the bat crawls. This curious modification of struc- 

 ture therefore is probably an indirect effect of living upon 

 an island where there are but few flying insects. From 

 the same group of animals may be drawn another example 

 of modification of structure having a relation to habitat. 

 In the Bermudas, which are 700 miles from the American 

 coast, are two species of bats ; but one only in the Azores, 

 which are closer to the island of Madeira by about 150 

 miles. The presence of these animals is said to be due 

 to the occasional prevalence of violent storms. It is 

 remarkable that these species have a robuster and more 

 hairy body, which would of course tend to endow them with 

 a greater power of withstanding the violence and coldness 

 of a long-continued gale. 



Another highly remarkable association of structure 

 with locality is afforded by the flightless insects of many 

 oceanic islands. Attention has been already directed to 




CH. IV] LEPIDOPTERA OF ISLE OF MAN. 217 



the fact that in the Galapagos and Kerguelen many of 

 the insects are flightless. The same is the case with 

 other oceanic islands. But in other cases the insects 

 have larger wings than their allies upon the mainland. 

 These two facts are both explained in the same way by 

 Mr Darwin. The small size of the islands and the frequent 

 prevalence of gales of wind would tend to blow the insects 

 out to sea, where they would in all probability perish. 

 Those individuals therefore which either had wings un- 

 commonly strong or were incapable of flight altogether 

 would have the best chance of maintaining their footing. 

 The same need has thus produced two effects of the most 

 opposite kind. 



Prof. Eimer has remarked upon the fact that "the 

 butterflies of Sardinia are in general smaller and also 

 more darkly coloured than those of the mainland." The 

 same thing exactly is met with in the case of the variety 

 of the small Tortoiseshell butterfly upon the Isle of Man. 

 This island has other insects which are darker in colour 

 than those upon the neighbouring mainland. Diantlicecm 

 capsophila is a variety of the more usual D. carpoplwga ; 

 in Ireland the examples of this variety are dark coloured, 

 but those of the Isle of Man are more darkly coloured 

 still. Mr Wallace mentions four other moths which show 

 some such difference from their representatives upon the 

 mainland. The somewhat rare Cirrhcedia xerampelina is 

 not much darker than the mainland form but it differs 

 from it in the production of a characteristic yellow line. 

 The late Mr J. Jenner Weir, a well-known entomologist, 

 noted that several of the Geometer moths of the Hebrides 




218 BIRDS OF GALAPAGOS. [CH. IV 



had a tendency towards a greyer coloration than the 

 specimens of the same species on the mainland. This alte- 

 ration he was disposed to put down to a colour variation 

 of a protective significance in relation to the abundant grey 

 gneiss of the islands ; it may however be a phenomenon 

 like the other instances that have been just mentioned. 

 It has been suggested that this prevailing melanism of 

 the insects of islands is an effect of the moist climates of 

 islands. On the other hand Mr Wallace noticed a 

 prevalence of white in the colour patterns of some of 

 the butterflies of the Moluccas and New Guinea, a 

 peculiarity more likely perhaps to be due to a possible 

 action of natural selection than the more usual darker 

 colour. The colour in this case would increase the con- 

 spicuousness of the insects ; but in an island they would 

 run less risks from insect-eating foes and might therefore 

 develop more freely in certain directions than on the 

 mainland, where enemies are more numerous and com- 

 petition severer. 



Precisely the same class of characters distinguish the 

 birds of the Galapagos islands 1 . The genus Geospize, a 

 finch peculiar to the islands and consisting of eight species, 

 is of a dull colour to black, the darker hues being the 

 distinctive mark of age. " In old males," says Mr Salvin, 

 " the plumage is almost uniformly black." Such specific 

 names as "fuliginosa" and " nebulosa" keep the pecu- 

 liarities of these insular birds in the mind. Cactornis, 

 another genus restricted to the islands, is "olivaceo- 



1 On the Avifauna of the Galapagos Archipelago. Trans. Zool. Soc. 

 Vol. ix. 1876, p. 447. 




CH. IV] OWLS OF GALAPAGOS. 219 



fusca" dorsal ly, and the species is called by Messrs Sclater 

 and Salvin "pallida" which is significant. Mr Salvin 

 thinks that the species may have been founded upon 

 birds not adult. These statements however do not only 

 apply to genera which are peculiar to the islands and 

 occur nowhere else ; indeed they would have much less 

 interest and significance if they did. One of the two Owls 

 living in the Galapagos, Asio galapagensis, is defined 

 by Mr Salvin as " Asioni brachyoto similis, sed minor, 

 coloribus obscurioribus" &c. The Xight Heron of the 

 Galapagos, whether it is a distinct species or merely a 

 variety of the common Nycticorax wolaceus, is stated to 

 be darker coloured than that species, and further instances 

 of a like nature might be brought forward from Mr Salvin's 

 monograph upon the birds of these islands. Generally 

 speaking his Latin diagnoses of the species abound with 

 such words as "niger," " nigerrimus," " fuscus," "fuli- 

 ginosus," &c., and completely bear out what has been 

 already said of the coloration of island forms belonging 

 to this as well as of other groups of the animal kingdom. 




CHAPTER V. 



SOME THEOKETICAL CONSIDERATIONS. 



The bearing of the facts of distribution upon the 

 places of origin of different groups. 



THERE seems to be little doubt that life first originated 

 in the sea, whence it spread to the fresh waters and so to 

 the land. We are not however concerned in the present 

 volume, which only professes to deal with the distribution 

 of terrestrial and a few fresh-water groups, with this 

 problem. 



But it is necessary to see how far the existing and 

 past facts of distribution enable the place of origin of a 

 particular terrestrial group to be indicated with prob- 

 ability. No exhaustive survey of the different groups of 

 the animal kingdom will be attempted ; but a few facts 

 and suggested explanations will be put forward as 

 examples. 



In some cases, of course, palaeontology throws a clear 

 light upon the problem. The horse, for instance, 'came 

 into being in the new world, whence it migrated into the 




CH. V] ORIGIN OF PARROTS. 221 



old world, becoming for a time extinct in its place of 

 origin; it was subsequently reintroduced, apparently by 

 man. An instance of this kind shows how careful we 

 must be to guard against the assumption that that locality 

 where a given group is most abundant is its place of 

 origin. It is perhaps a stronger argument to use the 

 locality of the more ancient forms of the group as being 

 probably the cradle of the race. 



Fiirbringer has lately urged the antiquity of the genus 

 Stringops, the flightless parrot of New Zealand; this 

 coupled with the presence of abundant parrots in the 

 Australian region many of them being primitive forms 

 that have preserved the ambiens muscle missing in many, 

 the normal arrangement of the carotids and a completely 

 developed clavicle argues for that region as being the 

 starting-point of the Parrot tribe. Here we are not 

 helped to any great extent by palaeontology. 



The different regions into which the world is divided 

 possess, as has been pointed out in some detail, in every 

 case a characteristic fauna. That fauna may be or may 

 not be autochthonous; the American Edentates seem to 

 have arisen where we now find them, since no fossil 

 Edentates are known of the American type save in 

 America. Other countries are peopled by immigrants. 

 There can be no doubt that wherever the groups of ani- 

 mals that inhabit oceanic islands arose it was not in those 

 islands ; there is clear evidence that they are the more or 

 less modified descendants of animals that found their way 

 across the sea in some way. 




222 THE DINGO. [CH. V 



The place of origin of the Marsupials. 



The Australian region offers difficulties which have 

 perhaps been passed over too lightly.- As is well known 

 the continent of Australia and some of the adjacent 

 islands to the northward are mainly characterised by 

 Marsupials. With the exception of the American 

 Opossums all the Marsupials are crowded into this com- 

 paratively limited tract of continent and island. In 

 addition to Marsupials there are of course the ubiquitous 

 bats, the Dingo dog and a few rodents, notably the genus 

 Hydromys, with more than one species. The Dingo has 

 been regarded as the feral descendant of a domesticated 

 dog introduced by man. M'Coy has however demon- 

 strated the existence of fossil remains of this Carnivore in 

 the Pliocene deposits of Australia, the remains of a period 

 when there were no human inhabitants of the continent. 

 On the other hand the proof has been strengthened by 

 investigations which approach the matter from another 

 side. Nehring denies that the osteological characters of 

 this dog are those of a feral animal, and affirms that it 

 presents all the features of a truly wild race. The 

 indigenous nature of the rodent inhabitants of Australia 

 have not been called in question. The line which 

 separates the Australian from the contiguous Oriental 

 region passes between the islands of Bali and Lombok and 

 between Borneo and Celebes, the last-mentioned island 

 being in each case within the Australian division. Lyell 

 shows in a sketch map of that part of the world that this 

 line (which has been called " Wallace's line ") nearly 




CH. V] LIMITS OF AUSTRALIAN REGION. 223 



coincides with a line marking off the range of the Indo- 

 Malayan and Pacific races of mankind. This remarkable 

 series of facts is usually accounted for in the following 

 way. The greater depth of water between the islands 

 mentioned probably indicates a longer time or separation 

 from each other than in those cases where the dividing 

 seas are shallower. Hence it may be assumed that the 

 dominant race of Mammalia in the earlier periods of the 

 earth's history occupied Australia in common with the 

 rest of the world ; at this time the deep separation 

 between the two regions, as we now admit them, took 

 place. Australia and the Australian region generally 

 would be well stored with Marsupials. So too would the 

 Oriental region. But in course of time the wave of 

 migration of higher types of mammals, the placental 

 mammals, evolved gradually from the Marsupial, would 

 extend eastward and improve the remaining Marsupials 

 off the face of the world ; the deep straits already referred 

 to might be reasonably held to offer an impediment to 

 their further progress eastward in sufficient numbers at 

 any rate to compete successfully with the mammalian 

 possessors of the soil. As a matter of fact the fringes of 

 the Australian region, the islands of Lombok and Celebes, 

 to wit, have received some few of these later migrants ; 

 " a baboon, a wild cat and a squirrel " occur in Celebes ; 

 while Macacus cynomolgus and one or two other placental 

 mammals reside in Lombok. This appears to be a 

 feasible explanation of the facts. But as already hinted 

 there are difficulties in the way of its immediate accept- 

 ance. To begin with, remains of the elephant have been 




224 THE MONOTREMATA. [CH. V 



dug up in Australia and in its furthest corner, viz. 

 Queensland. Furthermore, as the colonists know to their 

 cost, the common rabbit when artificially introduced has 

 proved capable of suiting itself with a marvellous degree 

 of success to the conditions found in Australia. In this 

 latter case no competition has had the least effect ; and 

 even when hampered by repressive legislation aided by 

 the experiments of bacteriologists the rabbit has done a 

 good deal more than hold its own. It is clear therefore 

 that there is nothing in the " air " of Australia which is 

 in any way fatal to the constitutions of mammals in 

 general. Then why, if the Marsupials have disappeared 

 elsewhere, have they not also disappeared from Australia ? 

 The key to the explanation of this difficulty seems to be 

 the assumption that Australia is the native country of 

 that group. It will be remembered that in Australia 

 alone and in some adjacent territories (New Guinea) are 

 there any representatives of the oldest order of Mammalia, 

 the Monotremata. The two existing genera Echidna and 

 Ornithorhynchus are unknown save in this part of the world. 

 It is generally accepted that the Monotremata stand 

 at the base of the mammalian series and that the 

 Marsupials stand between them and the higher mammals ; 

 the name Metatheria applied by Mr Huxley to the group 

 is an expression of this opinion. The very fact that 

 Marsupials abound in Australia is so far a proof that they 

 originated there ; for they would have died out were they 

 not so suited. Over-population or the migratory instinct 

 caused many forms to leave the Australian region and to 

 spread over Europe and America, in which latter country 




CH. V] IMPORTED ANIMALS IX AUSTRALIA. 225 



alone they have persisted. In fact the Marsupials have 

 had the start in a country eminently suited to them and 

 have only been beaten in the struggle for existence in 

 regions subsequently settled in by them and therefore 

 perhaps less fit for their peculiar organisation. There 

 still remains the puzzle why some races of animals have 

 been able to establish themselves in Australia in spite of 

 the existing mammalian fauna, and why others have not. 

 The case of the rabbit shows that we cannot get out of 

 this difficulty by assuming that as much colonisation as 

 there was room for has as a matter of fact taken place. 

 On this view we should regard the presence of the 

 elephant as an unsuccessful attempt at colonisation. The 

 presence of comparatively speaking numerous placental 

 Mammals on the outskirts of the Australian region 

 renders it impossible to have resort to the hypothesis that 

 colonisation was at such rare intervals that only the 

 Dingo and the other few Australian placental Mammals 

 have had time to establish themselves. The only way 

 out of this difficulty which at present suggests itself is to 

 dwell upon the superior energy of the younger races of 

 the Palsearctic region. 



It is generally held that the desert of Sahara was an 

 open sea during the Miocene period ; and that this checked 

 the immigration or emigration of many purely terrestrial 

 forms, and that it therefore formed a boundary between 

 the Ethiopian and Palsearctic regions. This boundary is 

 not accepted by everyone certainly ; but it is by some. Mr 

 Blanford has pointed out 1 that the geological views which 

 1 Presidential address to Geological Society 1890. 



B. z. L5 




226 PAST DISTRIBUTION OF MARSUPIALS. [CH. V 



argued a sea occupying the region of the Sahara during 

 tertiary times are now believed to have been erroneous. 

 Zittel, says Mr Blanford, has shown that there is no reason 

 to think that any part of the Sahara has been sea since 

 the Cretaceous period. This fits in admirably with the 

 present and past distribution of the Marsupials and in quite 

 a convincing way. There is of course abundant evidence 

 that these mammals were common in Europe during the 

 mesozoic epoch, whether they originated there or not. 

 Now if there was then land connection with the African 

 continent why did they not migrate there as well as to 

 Australia and to America ? It is of course possible that 

 they did and that they have since become extinct. 

 Madagascar however has to be considered; many writers 

 have pointed out that Madagascar appears to have 

 preserved some of the more ancient mammalian inhabi- 

 tants of the Ethiopian continent. In any case it seems 

 certain that many of the newer immigrants into Africa 

 never succeeded in getting as far as Madagascar. There 

 are so many analogies of a kind between Madagascar and 

 Australia that the negative fact that Marsupials do not 

 occur there gets a certain importance. If however the 

 severance between Africa and Europe was of earlier date 

 than is commonly held we have a possible explanation of 

 the entire (?) absence of Marsupials from the former 

 continent. Besides, their absence sheds perhaps an 

 oblique light upon my suggestion that the group origin- 

 ated in Australia. The numbers in Europe may have 

 been small, and there was therefore no pressure such as to 

 lead to migration. 




CH. V] SOUTHWARD MIGRATION OF ANIMALS. 227 



Theory of the Polar origin of Life. 



The theory of the polar origin of life 1 is, as regards 



terrestrial and fresh water vertebrates rather seductive. 



On this theory it is clear that the further away from the 



north pole the more archaic will be the types of animals 



met with ; and on the contrary the newer groups will 



have moved away to a less distance. Among the Mammalia 



this is strikingly exemplified of course by the Marsupials, 



once existing in great variety in Europe and North 



America. They are now absolutely extinct in Europe and 



but feebly represented in North America. The survivors 



have been pushed in to the furthest corner of the world 



the Australian continent, and some of the islands to the 



north. The bulk of the American Opossums are confined 



to the Neotropical, i.e. the more southern regions of the 



American continent, only a single species occurring in 



North America. This it is presumed upon the theory 



under discussion is due to the fresh development of types 



of life in the polar regions which have forced the older 



and less vigorous forms of life to emigrate ; a continued 



efflux of waves of life spreading out from the place of 



origin push further away the races which have the start. 



Everyone is agreed that the Struthious birds are in all 



probability an ancient race, or perhaps races, for the unity 



of the group is now-a-days rather called in question. 



Here again we meet with no northern types at all ; North 



Africa is the northern limit of the birds, and the vast 



1 See Haacke, Biol. Centrulblutt vi. 



152 




228 ANCIENT TYPES OF SOUTHERN HEMISPHERE. [CH. V 



majority are in the most southern parts of the globe ; 

 New Zealand itself had quite recently a number of species 

 as great as all the existing forms. The northern types of 

 birds, for instance the sandpipers, crows and hosts of 

 others, embrace no forms that can be regarded with any 

 probability as more ancient than the Ostrich tribe. 

 Among Reptiles the Hatteria, allied to the triassic 

 Hyper odapedon, has been driven quite to the verge of 

 inhabitable country ; it has even got beyond New Zealand 

 to a few small islands off the coast. Turning to another 

 group of animals, the Dipnoid fish exemplify what has 

 been said in a forcible way ; the three existing genera 

 Ceratodus, Protopterus and Lepidosiren are confined 

 respectively to Australia, South America, and certain 

 parts of Tropical Africa. The fossil remains of Dipnoi 

 are common in the more ancient strata of this country 

 and of North America. Even invertebrates fall in with 

 the theory to some extent. It seems on all grounds 

 reasonable to conclude that the genus Lumbricus, and 

 its immediate allies, are the most modern existing forms ; 

 these genera are precisely those which are indigenous to 

 the northern hemisphere only, where they form, with 

 a few exceptions, the only earthworms met with. 

 The more archaic Perichaetidse, Acanthodrilidse and 

 Cryptodrilidse are characteristic of the southern hemi- 

 sphere while the Acanthodrilidse which are very possibly 

 the oldest existing family of the group are particularly 

 antarctic in their range. The fresh water Crayfishes fall 

 in with the other groups cited ; and the facts in their 

 distribution and structure agree entirely with those of 




CH. V] RANGE OF ASTACID.E. 229 



the earthworms. Huxley 1 has divided the family into 

 two families the Potamobiidse and the Parastacidae ; the 

 former are confined to the northern the latter to the 

 southern hemisphere. Of the Potamobiidse there are but 

 two genera Astacus and Cambarus. In both of these the 

 pleurobranchs are greatly reduced, indeed in Cambarus 

 they are completely absent. As in Astacus there are distinct 

 rudiments of the pleurobranchs belonging to several pairs 

 of appendages, in addition to one pair completely developed; 

 the inference appears to be that the extra pleurobranchs 

 have in the course of time been lost. Now in all the 

 Parastacidae with the exception of Astacoides there are 

 four pairs of fully developed pleurobranchs, thus indicating 

 an earlier type. Furthermore the genera of the southern 

 hemisphere, " in which the apices of the podobranchise are 

 not separated into a branchial plume and a well developed 

 lamina, present a less differentiated type of branchial 

 structure than that which obtains in Astacus and Cam- 

 barus" Prof. Huxley himself is inclined to postulate the 

 existence of a marine ancestor of world wide distribution 

 which entered the rivers of the northern and the southern 

 hemisphere and diverged in different ways in each hemi- 

 sphere ; but this leaves unexplained why the antarctic 

 genera should have retained more primitive characters 

 than the Crayfishes of the north. 



There is another essential if the polar theory of the 



origin of life is to be accepted. To establish this theory 



upon a firm basis it will have to be proved that the 



faunas of the different countries become more and more 



1 The Crayfish in International Sci. Series. 




230 ARCTIC ANIMALS. [CH. V 



divergent the further they are removed from the hypo- 

 thetical seat of origin. This can be defended by a series 

 of facts. There has been of late a considerable amount of 

 discussion as to the value of the Palsearctic and Nearctic 

 regions of Mr Sclater. It has been proposed to unite 

 them into one common region to which the name Holarctic 

 has been applied by Prof. Newton. This is accepted by 

 Dr Heilprin in his work upon Geographical Distribution. 

 More recently Mr Wallace has defended the retention of 

 the two separate regions. The present object is not to 

 attempt to decide upon the relative values of these two 

 opinions but to emphasise the fact that there has been a 

 discussion, and to point out that there never has been any 

 question as to the distinctness of two such regions as the 

 Neotropical and the Oriental. An ingenious reconciliation 

 has been suggested by Dr Hart Merriam who would 

 institute a Boreal region cut off from Nearctic, and joined 

 to the Pala3arctic leaving the rest of the Nearctic alone 

 as a distinct " Southern " region. This proposal brings 

 into prominence the very close resemblance of the circum- 

 polar fauna; indeed out of the 30 genera of mammals 

 in the Boreal region only 10 are peculiar to America. 

 If we were to adopt a slightly different plan and cut off a 

 boreal region or Arctic region as it has been termed from 

 both Palsearctic and Nearctic the almost complete identity 

 of the circumpolar fauna would be clearly demonstrated. 

 Such animals as the Reindeer, the Glutton, the Elk, the 

 Lemming, the Arctic Fox are circumpolar in range. 

 Between the Palsearctic and the Nearctic, after this large 

 slice has been cut off from both, there is not a little 




CH. V] FOSSIL FLORA OF GREENLAND. 231 



likeness, though there are also differences. Moving 

 further south the differences increase until the resem- 

 blances almost entirely vanish. 



ts 



It is unnecessary to recapitulate the characters of 

 the faunas of the several regions here, as the matter has 

 been already treated of. Broadly speaking it is unques- 

 tionably the fact that the differentiation of the different 

 regions gradually increases as we pass southwards from 

 the north pole. We cannot of course hope to reduce to 

 an exact table the progressive differentiation of the fauna 

 along the lines of migration ; some have moved more 

 rapidly, others have lagged behind ; while structural 

 changes have proceeded more rapidly in some groups 

 of animals than in others. But a survey of the facts 



V 



tends to prove the general accuracy of the conclusion that 

 the differentiation of faunas proceeds more rapidly the 

 further we get from the pole. 



It is obvious that if life originated at the north pole 

 the conditions of climate must have been more favourable 

 than at present. That this was so there is abundant 

 evidence to prove. The existence of a luxurious and at 

 least subtropical fauna in the arctic regions during the 

 Miocene period is justly termed by Mr Wallace " one of 

 the most startling and important of the scientific discoveries 

 of the last 20 years." In remote Greenland we find 

 abundant and well preserved remains of chestnut, walnut, 

 plum, vines and even magnolias. Further north still in 

 lat. 78 and 79 there was in Spitzbergen an almost equally 

 rich fauna, of which one member the swamp cypress 

 (Taxodium distichum) is now a dweller in the southern 




232 GLACIAL EPOCHS. [CH. V 



United States. Water lilies, pond weeds, and an iris, 

 flourished at the same time in the same place. This 

 however does not indicate by any means the limits of 

 life towards the pole ; in Grinnel land distant only 

 8J degrees from the pole itself there was a flora composed 

 of poplars, elms, hazels and the swamp cypress again. 

 This warm period preceded the glacial period, which of 

 course put an end to the flora and fauna or else drove it 

 southwards. It is the opinion of many that the glacial 

 period was not an isolated phenomenon but the last in 

 a series of many glacial periods. If this were so 

 and if they recurred with tolerable frequency as is 

 again the opinion of many, all question of a polar 

 origin of life would be out of the range of possibility. 

 This view of the matter has been mainly based upon 

 two series of facts. In the first place it is argued that 

 these glacial periods have been due to the variations 

 in the obliquity of the earth's orbit, which alternates 

 from a more to a less pronounced ellipse. This would 

 bring about in conjunction with the rotation of the 

 earth on its own axis long cold winters and short hot 

 summers as well as the reversed condition. The former 

 would it is thought account for glacial periods. That 

 these have taken place in the recurrent fashion demanded 

 by this astronomical cause is attempted to be proved by 

 the existence of erratic boulders imbedded in the sedi- 

 mentary rocks belonging to past epochs. Mr Wallace 

 however holds that this cause is not of itself sufficient to 

 cause excessive glaciation ; it is necessary also to have 

 continuous land surfaces and high mountains to retain the 




CH. V] PALEOZOIC GLACIAL PERIODS. 233 



snow and ice and to prevent the influx of warm currents 

 from more southern latitudes. The undoubted boulders 

 he regards not as evidence of exceptional glaciation, but 

 as evidence of high mountains with glaciers which carry 

 down these boulders ; this is not inconsistent with a warm, 

 even tropical, temperature at their base. It is not until 

 we reach the Permian period that Mr Wallace thinks that 

 a severe glaciation occurred. In the west of England 

 there are beds of ice-borne rocks which must have been 

 carried for a distance of fifty miles and this together with 

 the poverty of the fauna and flora are indications of a 

 glacial period. If however we consider as Prof. Huxley 

 did in 1870 that even the highest group of animals the 

 mammalia probably originated well within the Palaeozoic 

 period, since it has taken from the commencement of the 

 Eocene to almost to-day for so small a modification as the 

 reduction of the horse's foot from the five-toed to the 

 one-toed condition, even this remotely distant glacial 

 epoch will be sufficiently near to exclude all possibility 

 of the polar origin of mammalian, let alone all other 

 vertebrate and invertebrate life. We may take it therefore 

 that the polar regions enjoyed a mild or even a warm 

 climate throughout the tertiary and secondary epochs, 

 but it has been pointed out that in Carboniferous and 

 Silurian times the temperature judging from the fauna 

 and flora was of the same kind ; this however is of no 

 importance from the present point of view if the Permian 

 glacial period really took place as the evidence seems to 

 assert. 





INDEX. 



Acanthisita, 201 

 Acanthodrilidae, 58, 60, 05 

 Acanthodrilus, 57, 60, 65, 66, 67, 



111, 169, 170; georgianus, 67; 



Kergueleneusis, 194 ; monocystis, 



65 ; verticillatus, 180 

 Aceros, 106 



^Eolosoma, Eange of, 140 

 ^Eluroidea, 188 

 ^Jluropus, 90, 92 

 yElurus, 90, 92, 106 

 Africa, Scorpions of, 57 : and 



Europe, Affinity between, 43 

 Agaristidae, 130 

 Aglossa, 47 

 Alectoromorpha, 75 

 Alectoropodes, 27, 28, 29 

 Alligator, 43, 44; sinensis, 44 

 Alligators, Mississippi, 3 

 Allolobophora, 152; Japonica, 153 



note 



Allurus, 152; tetraedrus, 57 

 Amblyrhynchus, 148, 196, 197 

 America, Scorpions of, 52 

 Amphibia, Dispersal of, 145 ; Uro- 



dele, 47 ; and fishes, 178 



Amphignathodontidas, 48 



Amphisbaena ridleyi, 191 



Amphisbaenidae, 41 



Anabas scandens, 2 



Anacharis, 128 



Anelytropidae, 41 



Anguidse, 41, 42 



Animals, Habitats of, 3; General 

 facts of the distribution of, 

 1-70; Introduced, 129; Land, 

 distribution of, 4; Locality and 

 station of, 5; Means of disper- 

 sion of, 134 ; Eange of, 7 ; Ter- 

 restrial and aquatic, 2 



Annadrilus, 63 



Annelids, 138; Terrestrial, 168 



Anoa, 107 



Anodonta, 144; anatina, 142 



Anomalopteryx, 202 



Antarctic Continent, 164 



Antarctogaea, 74 



Anteaters, Eange of, 31 



Anteus, 64 



Anthropopithecus calvus, 99, 101 




236 



INDEX. 



Antilocapra, 96 



Apes, Anthropoid, 106 



Apis mellifica, 128 



Apoxypodes, 50 



Aptenodytidse, 76 



Apteryx, 200, 202, 210 



Aptornis, 202 



Aramus, 109 



Archisometrus, 51 



Arctocebus, 102 



Arctogaea, 74, 75 



Arctonyx, 106 



Arcturides cornutus, 125 



Arcturus americanus, 125; baffini, 

 125; coppingeri, 125; furcatus, 

 125; oculatus, 125; Shallow 

 water and deep sea, 126; steb- 

 bingi, 125 ; studeri, 125 ; Eange 

 of, 125 



Argilophilus, 69 



Argus, 29 



Arion, 145 



Armadillos, 31, 111 



Arthropods, 17 



Asio galapagensis, 219 



Aspidonectes, 148 



Astacilla, 125, 126 ; marionensis, 

 125 



Astaeus, 229 



Athecae, 38 



Atheriogaea, 75 



Atherura, 104 



Attagis, 110 



Australia, Frogs of, 172 



Australian Kegion, Families pe- 

 culiar to the, 113, 114; sub- 

 regions, 116, 117 



Avifauna of Australian region, 115 



Baboon, Gelada, 101 



Badger, its habitat, 5 



Balaeniceps, 100, 101 



Barbets, 110 



Bassaris, 25, 94, 109, 112 



Batrachia, Distribution of, 47 



Batrachians, 80 



Bats of New Zealand, 215 



Bear, Present and past range of 



the, 154 



Bears, Distribution of, 22 

 Beetles, "Hercules and Goliath," 



129 



Belemnites, 182 

 Belodon, 148 



Benhamia, 59, 65, 67, 170 

 Bernicla sandvicensis, 204 

 Bernissartia, 44 

 Bipalium, 55 ; Kewense, 54, 55 

 Boas, 46 

 Boidae, 46 

 Bolieria, 46 

 Brachylophus, 77 

 Brachytarsomys, 188 

 Brachyurus, 111 

 Bradypodidse, 31 

 Bradypus, 31, 111 

 Brazilian sub-region, 111 

 British Isles, Fauna of, 183 

 Brontornis, 167 

 Bucerotidae, 75 

 Bufo dialophus, 77, 147 note 

 Bufonidae, 47 

 Buteo solitarius, 204 

 Buthidae, 50 

 Butterfly, Large copper, 7 



Cacatuidae, 114 

 Cactornis, 197, 218 

 Caiman, 43, 44 

 Californian sub-region, 36 




INDEX. 



237 



Callidrilus, 63 



Calodronias, 111 



Calophrynus, 178 



Camarhynchus, 197 



Cambarus, 229 



Canadian sub-region, 97 



Cancroma, 110 



Cannonopsis, 194 



Capra aegagrus, 21; caucasica, 21; 

 falconeri, 21 ; hylocrius, 22 ; 

 ibex, 21 ; jemlanica, 21 ; pal- 

 lasii, 21; pyrenaica, 20; severt- 

 zowi, 22; sibirica, 21; sinai- 

 tica, 21 ; walie, 21 



Capromys, 112 



Cariama, 109, 167 



Cariamidas, 76 



Carinate birds, 82 



Carpococcyx, 107 



Casarca, 46 



Cassowaries, Distribution of, 23 



Cassowary, Species of, 23 



Castniidae, 130 



Casuarius australis, 23 ; Beccarii, 

 24; Bennetti, 24; bicaruncula- 

 tus, 24; Edwardsi, 23; galeatus, 

 23 ; laglaizei, 24 ; occipitalis, 24 ; 

 picticollis, 23 ; Salvadorii, 23 ; 

 uniappendiculatus, 23; Wester- 

 manni, 23 



Cathartidae, 76 



Celebes, Fauna of, 106 



Central or Kocky Mountain sub- 

 region, 96 



Centropus, 36 



Centrurus, 52 



Ceratodus, 228 



Ceratophrys ornatus, 48 



Cercophonius, 52 



Cereopsis, 202 



Ceriornis, 89, 93, 106 



Certhidea, 197 



Ceylonese sub-region, 105 



Chalarodon, 189 



Chalk and Ooze, 158 



Champa, 96 



Chamaeleon, 32, 190 



Charnaeleons, Kange of, 41 



Chasrnorhynchus, 129 



Chauna, 109 



Chelonia, Distribution of, 38 



Chelydidse, 39 



Chelydridae, 38 



Chilian sub-region, 110 



Chimpanzee, 13, 68, 99 



Chionis, 166 



Chiromyidae, 11 



Chiromys, of Madagascar, 14 



Chlamydophorus, 32, 110 



Chceropotamus, 100 



Cholcepus, 31 



Chrysochloridae, 102 



Cidarids, 158 



CinisternidaB, 38 



Cirrhaedia xerampelma, 217 



Civet, The, 91 



Cladocera, Eggs of, 136 



Cneiniornis, 202, 210, 211; calci- 



trans, 202 

 Ccelodon, 34 

 Coaloplana, 55 

 Coliidae, 100 

 Colossochelys, 214 

 Colour and distribution, 118 

 Colubridae, 46 

 Condylura, 97 

 Conolophus, 196 

 Coracopsis, 189 

 Corallus, 46 

 Coregonus vandesius, 8 




238 



INDEX. 



Cornufer, 47, 77 



Cosmopolitan genera, 9; groups, 

 8 ; species, 10 



Cotyloplana. 55 



Coua, 189 



Cracidae, 27, 28, 30, 31 



Cricetomys, 90 



Criodrilus, 64 



Crocidura, 188 



Crocodile hidden beneath a hay- 

 stack, 154 



Crocodiles, Distribution of, 43 ; 

 Marine, 148 



Crocodilus, 43, 44 ; palustris, 45 



Crossoptilon, 93 



Crotophaga, 36, 94 



Crustacea, Antarctic, 161 



Crustaceans, Isopod, 161 



Cryptodira, 38 



Cryptodrilidae, 58; Kange of, 68 



Cryptodrilus, 60, 69 



Cryptoprocta, 14, 188 



Ctenodactylus, 91 



Cuckoos, 105; Distribution of, 35; 

 Fossil, 37; Old World and New 

 World, 36 



Cuculidae, Distribution of, 35 



Cuculus canorus, 36 



Cuscus, 77 



Cyathopoma, 179 



Cyclostoma, 144 



Cyclostomatidae, 179 



Cyclotopsis, 179 



Cycloturus, 31 

 Cynomys, 97 



Cynopithecus, 104, 107, 116 

 Cystignathidae, 48, 172 



Dactylethridae, 47, 49 

 Dama, 91 



Dasornis, 167 



Dasypodidae, 31, 33 



Dasypus, 32 



Deinodrilus, 60, 65, 66, 169 



Dendrobatidae, 48 



Dendrogaea, 47, 74 



Dendrolagus, 117 



Deodrilus, 69 



Dermatemydidfie, 38 



Diachaeta, 64 



Dianthoscia capsophila, 217 



Diatryma, 167 



Dichogaster, 69 



Didelphys, 109 



Didunculidre, 77 



Digaster, 69 



Dingo, The, 115, 222 



Dinornis, 200, 202 



Dinornithidae, 167 



Dionychopodes, 50 



Diplocardia, 65, 67 



Diplocentridae, 53 



Diplocentrus, 52, 53 



Diporochaeta, 61, 169 



Discoglossidae, 48 



Discophidaa, 49, 178 



Distsechurus, 117 



Distribution, 118, 119, 124; Dia- 

 grams of, 119-121 ; Discontinu- 

 ous, 15 ; Geographical, 4 ; Plans 

 of, 81, 82; MrEomanes on, 132; 

 and evolution, 131 



Dolichoplana, 56 



Dorcopsis, 117 



Doriopsis, 84 



Doris, 84 



Drepanididae, 77, 204 



Dytiscus, 143 



Earth-worms, Aquatic, 138 ; Dis- 




INDEX. 



239 



tribution of, 57 ; Ethiopian, 67 ; 

 Families of, 58, 59; of Mada- 

 gascar, 180; of Mauritius and 

 Kodriquez, 181; of New Zea- 

 land, 66; of West Indies, 64 



East African sub-region, 101 



Eastern or Alleghany sub-region, 97 



Echidna, 32, 224 



Echinoderms, Fossil, 182 



Echinoids, 158 



Ectemnorhinus viridis, 194 



Edentates, 76, 111; Distribution 

 of, 31 ; Extinct, 34 ; Old World, 

 32; Structure of, 33 



Elainea ridleyana, 191 



Elaphodus, 92 



Elaphrornis, 106 



Elasmognathus, 109, 112 



Elephant, Indian, 104 



Elseya, 39 



Embryonopsis halticella, 194 



Emeus, 202 



Enhydra, 96 



Enchytraeidae, 139 



Ethiopian region, Families pe- 

 culiar to, 98 ; genera peculiar 

 to, 98, 99; sub-regions, 101 



Etroplus, 178 



Eublepharidas, 41 



Eudrilidae, 58 



Eudriloides, 68 



Eudrilus, 58, 67 



Eupleres, 188 



Eupetes, 107 



European sub-region, 91 



Eurypyga, 109, 111 



Eutheria, 86 



Evolution and Distribution, 131 



Fauna, affinities of, 192 



Faunas, Influence of geological 

 terrain upon, 136 ; Similarity 

 of the, hi different countries, 

 129; Synchronous, 163; of 

 Tropical countries, 130 



Fernando Noronha, Fauna of, 190 



Fish, Fresh-water, 171 



Flat worms, 3 



Flightless birds, 213 



Francolinus Kirki, 8 ; pictus, 29 



Fregilupus, 11 



Frog, The edible, 146 



Frogs and Toads, 47 



Galapagos, Birds of the, 218; 

 Fauna of the, 195; Insects of 

 the, 198; Owls of the, 219 



Galaxias, 171; attenuatus, 171 



Galaxiid, 171 



Gallinaceous birds, Distribution of, 

 26; Structure of, 28 



Gallus, Species of, 29 



Gammarus, 192 



Garrulus, 18 ; glandarius, 19 



Gastornis, 167 



Gavialis, 43, 44 



Geckotidae, 40 



Geobia subterranea, 55 



Geococcyx, 36, 96 



Geodesmus, 55 



Geographical distribution, 4 



Geomalacus maculosus, 186 



Geophilus ridleyi, 191 



Geoplana, 55, 56 



Geoscolex, 64 



Geoscolicidae, 58, 60, 62, 63, 181 



Geospiza, 197, 218 



Glauconiidaa, 46 



Globigerinag, 158 



Glyphidrilus, 63 




240 



INDEX. 



Goats, Wild, Range of, 21 

 Gordiodrilus, 66, 69 

 Gorilla, The, 11, 101 

 Graptolites, Range of, 160 

 Grosphus, 51 

 Gruidae, 75 

 Guinea-fowls, 29 

 Gymnura, 106 



Hallomys, 188 



Halobates, 2 



Haploceros, 96 



Haplochitonidae, 171 



Haploodon, 96 



Harpagornis, 203 



Hatteria, 12, 14, 40, 201, 210, 



228 



Heliciua, 179 

 Heliodrilus, 68 

 Helix desertorum, 144 

 Heloderma, 42 

 Hemichromis, 178 

 Hemiphractidae, 48 

 Henlea ventriculosa, 7 

 Hesperomys, 90, 196 

 Heteralocha, 201 

 Heterocephalus, 101 

 Heterodon, 189 

 Hippopotamus, 14, 100 

 Hoplurus, 189 

 Hormogaster, 63 

 Hormurus, 51 

 Humming-birds, 132 

 Hyama, 91 

 Hydromys, 222 

 Hydrophasianus, 105 

 Hydropotes, 92 

 Hylobates, 104 

 Hylodes, 48 

 Hyomoschus, 102 



Hyperiodrilus, 68 

 Hypocolius, 101 

 Hypogeomys, 188 



Ibex, 24; Stfarlet, 110; Spanish, 

 20 



Ibexes, Distribution of, 20 



Iguanidae, 41 



Ilyogenia, 63 



Ilysiidae, 46 



Indian sub-region, 105 



Indo-Chinese sub-region, 106 



Ireland, Mollusca of, 186 



Islands, Anomalous, 210; Com- 

 parison of, 205 



Isle of Man, Lepidoptera of the, 

 217 



Isometrus, 51 



Jays, Distribution of, 18 



Kerguelen, Fauna of, 193 

 Kerria, 65, 66, 169 

 Koala, 117 

 Kynotus, 63, 180, 181 



Laeertidae, 42 



Lacertilia, Distribution of, 40 



Lagopus albus, 29; scoticus, 184 



Lagothrix, 111 



Lama, 110 



Leimacopsis, 56 



Lemurs, 41, 100, 176; Diagram 



of range of, 123 ; Genera of, 



187 



Lepidosiren, 228 

 Lepidoptera, Range of, 6 

 Leptopoma, 179 

 Leptosoma, 189 

 Liopelma hochstetteri, 48, 201 




INDEX. 



241 



Liothrix, 106 



Lizard, African, in Cumberland, 

 154 



Lizards, Distribution of, 40; Mo- 

 nitor, 190 



Lophophorus, 89, 93 



Loris, 105 



Loxocenius, 46 



Loxops, 204 



Lumbricidae, 58, 62, 63, 169 ; 

 European, 154; Extra-Euro- 

 pean, 153 



Lumbricus, 63, 152, 228; papil- 

 losus, 186 



Lusciniola, 92 



Lutronectes, 92 



Lybiodrilus, 68 



Lycaena agestis, 186 ; Artaxerxes, 

 186 



Lycaon, 102 



Lynmaaa involuta, 186 ; peregra, 

 141; trunculata, 142 



Lynx, The, and the Bear in Europe, 

 155 



Mabuia punctata, 191 



Macacus, 104 ; cynomolgus, 223 



Madagascar, Fauna of, 187 



Malayan sub-region, 106 



Mammalia, 85, 86, 87 



Mammals, Distribution of, 74 ; 

 Past history of, 86 ; and Zoo- 

 logical regions, 85 



Man as a distributing agent, 152 



Manatee, 2 



Manidse, 32 



Manis, 33, 34, 104 



Mantchurian sub-region, 91, 92 



Mantella, 48 



Manucodia, 117 



Marsupial Mole, 117 



Marsupialia, 76 



Marsupials, 56, 114, 117, 222, 

 225, 226 



Mascarene birds, 177 



Mediterranean sub-region, 91 



Megalapteryx, 202 



Megapodes, 114 



Megapodidae, 27, 28, 30, 31 



Megapodius, 107 



Megascolex, 61; armatus, 180, 181 



Megaseolicidffi, 62 



Megascolides, 60, 69 



Megatheriidse, 33, 34 



Megatherium, 34 



Meleagridae, 27 



Meleagris, 30 



Mesites, 101, 189 



Metatheria, 86 



Mexican sub-region, 111 



Microchseta, 63 



Microdrilus, 69 



Microglossus, 117 



Microplana, 55 



Microscolex, 60, 68, 70, 111, 169, 

 170, 202 



Migration, 150, 151 



Millsonia, 69 



Mimus trifasciatus, 198 ; parvulus, 

 198 



Mollusca, Characters of, 84 ; Dis- 

 persal of, by insects, 143 ; Dis- 

 persal of land and fresh-water, 

 140; Migrations of, 142; of 

 ponds, 141 ; and Zoological 

 regions, 83 



Moniligastridae, 58 



Monitors, 42 



Monkeys, 11, 76 



Monotremata, 12, 76, 86, 113, 224 



B. Z. 



16 




242 



INDEX. 



Moschus, 90, 92 



Mud Fish, The, of Africa and 



America, 3 



Mus musculus, 193 ; rattus, 210 

 Musophagida3, 100 

 Mydaus, 106 

 Myogale, 91 

 Myrmecobius, 117 

 Myrmecophaga, 33, 34, 111 

 Myrmecophagidae, 31 

 Myro, 194 



Mystacina tuberculata, 200, 215 

 Myxomys, 112 



Naia tripudians, 149 



Nearctic Kegion, 93; sub-regions, 

 96 



Nebo, 53 



Nectogale, 92 



Nematoda, 136 



Neodrilus, 65 



Neogaea, 45 



Neosorex, 96 



Neotropical Region, families pe- 

 culiar to, 207 ; genera peculiar 

 to, 108; Sub-regions, 110 



Nepa, 142 



Nesomys, 188 



New Guinea, the original home 

 of the Cassowaries, 24 



New Zealand, Bats of, 215, 216; 

 extinct birds of, 202 ; Fauna of, 

 199 ; Flora of, 127 



Notogaea, 56, 75, 76 



Notonecta, 143 



Notornis, 201, 211 



Notykus, 68 



Novo-Zealanian sub-region, 118 



Numida, 30 



Numididae, 27 



Nyctereutes, 92 

 Nycticorax violaceus, 219 

 Nyctiornis, 105 



Oceanic Islands and submerged 



Continents, 157 

 Oceans, Permanence of, 156 

 Ocnerodrilus, 70 

 Octochaetus, 60, 65, 66, 169 

 Ocydromus, 201 

 (Eneis jutta, 16 

 Oligochasta, 58 ; Dispersal of, 138, 



139; terricolae, 169 

 Onchidium, 3 

 Onychochaeta, 64 

 Opisthacanthus, 53 

 Opisthocentrus, 53 

 Opisthodactylus, 167 

 Opisthocomidaa, 27, 76 

 Opisthocomus, 11, 27, 109 

 Orang, 104, 106 

 Oriental Kegion, Families peculiar 



to the, 103 ; genera peculiar to 



the, 103 ; Sub-regions, 105 

 Ornithogaaa, 75 

 Ornithorhynchus, 224 

 Ornix devoniella, 11 

 Orycteropodidae, 32, 34 

 Orycteropus, 33, 34 

 Ostolasmus, 43, 44 

 Ostracod, 192 

 Ostrich tribe, 29 

 Otidiaa, 75 

 Ovibos, 97 

 Ovis montana, 96 

 Owl, The Barn, 7 



Pachyornis, 202 



Palsearctic Kegion, 88, 89 ; Sub- 

 regions, 91 




INDEX. 



243 



Palaeogasa, 45 



Palaeoperdix, 29 



Palaeophonus, 50 



Palaaornis, 105 



Palseortyx, 29 



Palamedea, 109 



Palamedeidse, 76 



Paludina, 144 



Panthalops, 92 



Panurus, 91 



Papuan or Austro-Malayan region, 



116 



Paradisea, 117 

 Paretroplopus, 178 

 Parrots of the Australian region, 



115; Origin of, 221 

 Parus ater, 184; britannicus, 184; 



palustris, 16; rosea, 184 

 Passerines, 72-74 

 Patula hookeri, 194 

 Peacock, 29 

 Pectinator, 101 

 Pedetes, 102 

 Pedioccetes, 97 

 Pelamys, 149 

 Pelomedusa, 39 

 Penguins, 166 

 Pennula ecaudata, 204 

 Perichaeta, 59, 61, 62, 169, 181; 



indici, 180 ; rnadagascariensis, 



180 ; mauritiana, 181 ; robusta, 



181 



Perichaetidae, 61, 62 

 Perionyx, 61; zanzibaricus, 62 

 Periophthalmus, 3 

 Peripatus, 16, 26; Range of, 17 

 Peristeropodes, 27, 75 

 Perodicticus, 101 

 Perosuchus, 43, 44 

 Phcenicophaes, 35, 37 



Phasianidae, 27 



Phasianus, 89, 93 



Pheasant, 29 



Philodryas, 189 



Phororhacus, 167 



Photodilus, 105 



Phyllodactylus, 196, 197 



Phytogeography, 4 



Phytosus atriceps, 194 



Piaya, 36 



Pigeons of the Australian region, 



115 



Pipa, 48 

 Pipidae, 47, 48 

 Pisidium pusillum, 141 

 Pithecia, 111 

 Pitta, 102 

 Pixys, 39 



Plagiochaeta, 60, 65, 66, 169 

 Planarians, Land, 53, 56 

 Planorbis, 191, 192; corneus, 141; 



nautilus, 141 



Platacanthomys, 105, 106 

 Platypus, 117 

 Platysternidae, 38 

 Pleurodira, 38 



Plumatella, Statoblasts of, 136 

 Plutellus, 69 

 Podocnemis, 39, 40 

 Poecilophycis, 194 

 Polar origin of life, Theory of, 



227 



Polycladus, 56 

 Polynesian sub-region, 117 

 Polyommatus dispar, 185 

 Polytoreutus, 68 

 Pontodrilus, 57, 70 

 Pontoscolex, 58, 64, 70; corethru- 



rus, 192 

 Poospiza, 97 




244 



INDEX. 



Porcupine, 91 



Potamochaerus edwardsi, 188 

 Potamogale, 102 

 Praechidna bruijnii, 117 

 Priodon, 32 

 Procarpa, 92 

 Productus, 163 

 Prosthemadera, 201 

 Pro teles, 102 

 Protopterus, 228 

 Psammomys, 91 

 Pseudapteryx, 202 

 Psittinus, 105 

 Psophia, 109, 111, 167 

 Psophiidae, 11, 76 

 Pteroclidae, 75 

 Pteromys, 104 

 Pteropidae, 77 

 Pucrasia, 93 

 Puma, The, 94 

 Pupa, 85 

 Pygopodidae, 42 

 Pyrophthalma, 92 

 Pythons, 46 



Querquedula eatoni, 193 



Babbits in Australia, 129 



Rana esculenta, 146 ; guppyi, 47, 

 77 ; mascarina, 176 



Eatitae, 76 



Kegion, Holarctie, 78, 80; Poly- 

 nesian, 77 



Regions, Arctic and Antarctic, 76; 

 Hepetological, 79 ; Mr Huxley's, 

 75; Mr Sclater's, 72, 78, 88; 

 Use of birds for defining, 82 



Reptiles, Dispersal of, 147 ; of 

 the Galapagos, 196 ; and Ocean 

 barriers, 149 



Restricted groups, 10 

 Rhacophorus, 49, 178 ; reimvardti, 



49 

 Rhea, 111 ; Distribution of, 19 ; 



Species of, 20 

 Rhea americana, 19, 20; darwini, 



19, 20; macrorhyncha, 19, 20 

 Rhinoceros, 99 

 Rhinochetidaj, 11, 77 

 Rhinodrilus, 64 

 Rhynchocephalia, 12 

 Rhynchodemidae, 55 

 Rhynchodemus, 55 

 Rodents of Madagascar, 188 

 Rotifers, 136 



Salmo perisii, 185 



Salpinctes, 97 



Sandwich Islands, Fauna of, 203 



Schistocerca literosa, 199; melano- 



cerca, 198 

 Scincidas, 40 

 Scopus, 100 



Scorpions, Distribution of, 49 

 Scotophilus tuberculatus, 200 

 Sea-lions, 168 

 Sea-serpent, 168 

 Selasphorus rufus, 97 

 Seleucides, 117 

 Semuopithecus, 106 

 Serolis, 172; distribution of, 175; 



species of, 173, 174 

 Serolis carinata, 174, 176; minuta, 



175 ; paradoxa, 174 ; septem- 



carinata, 175 



Seychelles, Mollusca of, 179 

 Siamanga, 104 

 Siberian sub-region, 91, 92 

 Siphonogaster, 63, 138 

 Skunk, The, 94, 109 




INDEX. 



245 



Sloths, Range of, 31 



Snakes, Colubrine, 46 ; Distri- 

 bution of, 46 



Solenodon, 112 



South -African sub-region, 102 



Sparganophilus, 64, 187 



Sparrow, The, in the U. S., 128 



Sphaerium lacustre, 141 



Sphargis coriacea, 38 



Spirobolus noronhensis, 191 



Steatornis, 110 



Sterna virgata, 193 



Sternothaerus, 39 



Stringops, 201, 221 



Strix flammea, 7, 197 



Stuhlmannia, 68 



Stumpffia, 48 



Sturnornis, 106 



Subarctic sub-region, 97 



Sub -regions, Mr Mitchell's scheme, 

 122 



Succinea, 144 ; Eggs of, 142 



Sus, 116 



Taeniogale, 105 



Talegalla lathami, 29 



Tamandua, 31 



Taoperdix, 29, 30 



Tapinostola bondii, 6 



Tapirs, The, of America and India, 



131; Indian, 106; Malayan, 104, 



109, 111 



Tarsius, 104, 106, 116 

 Tatusia, 32 



Taxodium distichum, 231 

 Teguexin, 42 

 Teiidae, 42 

 Testacella, 145 

 Testudo, 39, 214 

 Tetrao urogallus, 28 



Tetraonidae, 27, 30 



Thaumalea, 89, 93 



Thecophora, 38 



Thinocoris, 110 



Thylacine, 14, 117 



Timelia, 107 



Timeliidaj, 104 



Tinarnous, 76 



Tityobuthus, 51 



Tityus, 53 



Todus, 112 



Tolypeutes, 32, 110 



Tomistoma, 43, 44 



Tortoises, Distribution of, 38 ; 



Giant, 213, 214 

 Trichochseta, 64 

 Triuephrus, 69 

 Trionychoidea, 38, 39 

 Trionyx, 39 

 Trochilidaa, 76 

 Trogons, 110 



Tropidonotus tessellatus, 149 

 Tropidurus, 196 

 Tubifex, 7 



Turbellaria, Triclad, 54 

 Tykonus, 64 

 Typhaeus, 69 

 Typhlopidaa, 46 



Ungulata, 76 



Ungulates, The, 104 



Unio, Australian, 141 



Upupidaa, 75 



Urobenus, 64 



Urocissa, 106 



Uropeltidae, 46 



Urotrichus, 96 



Ursus, 22; arctos, 90, 154; ferox, 



90 

 Urva, 106 




246 



Volucella, 129 

 Vanessa cardui, 7 

 Varanidae, 42 

 Vespertilionidas, 77 

 Vireo gracilirostris, 191 

 Vulturidae, 75 



West-African sub-region, 101 

 West-Indian sub-region, 112 

 Woodpecker, 32 



INDEX. 



Wombats, 117 



Xenicus, 201 

 Xenopeltidas, 46 

 Xenosauridas, 42 

 Xenurus, 32 



Zenaida maculata, 191 

 Zonites, 85 

 Zoogeography, 4 

 Zosterops, 129 



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