NATURE 



193 



THURSDAY, JUNE 26, 1890. 



ZOOLOGICAL GEOGRAPHY. 



La Geographic Zoologique. Par le Dr. E. L. Trouessart. 

 Avec 63 figures intercaldes dans le texte et deux 

 cartes. (Paris : J. B. Bailliere et Fils, 1890.) 



DR. TROUESSART, author of a "Catalogue des 

 Mammif^res Vivants et Fossils," and until recently 

 Curator of the Museum at Angers, has enriched the 

 Biblioth6que Scientifique Contemporaine with a most 

 interesting and valuable book on zoological geography. 

 This work must have caused its author a great amount of 

 labour, to judge from the painstaking way in which he 

 has worked in the facts collected by numerous specialists. 

 Their results, and those of his many predecessors in the 

 fascinating field of the distribution of animals, have been 

 augmented by his own views, and have been condensed 

 into a form which it is agreeable and easy to read. 



The first six chapters are devoted to a description of 

 the various zoo-geographical regions as they are now 

 generally accepted. The different types of animals which 

 are to serve as a basis for the investigation of the laws 

 of geographical distribution are grouped in four classes, 

 according to their means of dispersion and their usual 

 habitats : terrestrial, fresh-water, aerial — t.e. provided 

 with wings — and marine. The author has greatly in- 

 creased the value of his book by the graphic method he 

 has employed to show the distribution of given groups of 

 creatures. 



The general scheme is given on p. 175, the eight regions 

 into which the author divides the globe being indicated 

 by blocks, which are arranged and connected with each 

 other as follows : — 



Arctic Region 

 Palsearctic Region Nearctic Region 



Ethiopian Region — Oriental Region Neotropical Region 

 Australian Region 

 Antarctic Region. 



The mammalian distribution, when expressed by such 

 a lucid scheme, comes out thus : — 



Arctic 

 I 

 Holarctic ' 

 I I 



Ethiopian Neotropical 

 Australian 

 Antarctic. 



This indicates that, so far as mammals only are con- 

 cerned, the Palaso- and Nearctic regions are practically 

 one, while the Oriental is merged in the Ethiopian 

 region. Australia stands, of course, alone ; but that this 

 continent must have been once connected with the Indo- 

 Malayan countries is strongly indicated by the dingo and 

 several other, chiefly rodential, placental mammals in 

 Australia. The discovery by Prof, MacCoy of fossil 

 bones of the dingo in Pliocene strata of Victoria disposes 



' For Holarctic the more convenient and more correct name of the Peri- 

 arctic region might be substituted. Holarctic should logically include the 

 Arctic together with its subdivisions. Triarctic, an American term, means, 

 of coarse. Arctic + Palasa + Nearctic, while Periarctic would indicate 

 what is wanted— namely, the Holarctic minus the Arctic region.— H. G. 



at once of the hypothesis of its having been introduced 

 by man. ' 



The distribution of reptiles (p. 204/) is almost entirely 

 based upon G. A. Boulenger's results, as published by him 

 in the " Catalogue of Lizards and Tortoises in the British 

 Museum," and shows to what valuable account such a 

 publication can be turned if worked out upon a proper 

 basis : — 



(Palaeogaea) 

 Occidental -k- Oriental 



(Neogaea) 

 Nearctic Region 



African Au.stralian and 



Polynesian Regions 



New Zealand Region. 



Neotropical Region 



This scheme indicates that in the distribution of rep- 

 tiles the principal relationships range vertically, with few 

 or hardly any (except, of course, in Europe and Asia) trans- 

 verse or longitudinal similarities. The globe is practically 

 divisible into two great regions — namely, into Neogaea and 

 Palaeogaea, or into an American, Oriental, and Occidental 

 region, New Zealand being a remote and peculiar 

 appendix of the Oriental portion. 



On p. 215 /, terrestrial insects, especially Coleoptera, 

 are discussed. The two Polar regions possess a few 

 forms only, and need hardly be considered. The Hol- 

 arctic region, connected by the broad vertical belt of 

 Polynesia and the west coast of both Americas with the 

 Australian, New Zealand, and Patagonian regions, is 

 comparatively poor in Coleopterous types, and the forms 

 which occur have certain resemblances in common. Two 

 large centres of rich development in forms and numbers 

 are the Indo-African or Ethiopian, and the Brazilian or 

 typical Neotropical regions. 



Region Microtypique (Nord) 



Indo-African Polynesia 

 Region 



Brazilian 

 Region 



NO. 1078, VOL. 42] 



Australia Patagonia 



New Zealand 

 Region Microtypique (Sud). 



The division of the globe into Palaeogaea and Neogaea 

 is equally applicable to the Arachnids, the differences 

 between Arcto and Notogsea being of by far less im- 

 portance. Arachnid regions are : (i) Palaearctic, (2) 

 Ethiopian, (3) Oriental, (4) Australian, (5) American. The 

 whole of America has practically an Arachnid fauna from 

 north to south, and it is divisible into eight sub-regions, 

 which do not correspond with those of Wallace. The 

 Ethiopian Arachnid region comprises the whole of Africa 

 south of the Atlas, and Central Arabia ; it has therefore 

 been called the Libyan region, since it differs by the 

 whole extent of the Sahara from the Ethiopian region 

 of Wallace. The Oriental and Australian regions are 

 those of Wallace, but the Oriental includes Madagascar 

 and South-Eastern Africa as a sub-region. Certainly, so 

 far as Coleoptera and Arachnida are concerned, Mada- 

 gascar is much more Malayan than African. The 

 Palzearctic region, as a whole, is that of Wallace, but 

 the four sub-regions are differently arranged — namely, 

 Europeo-Siberian, Hispano-Italian (Western Mediter- 

 ranean and Canary Islands), Taurian or Eastern Medi- 

 terranean, with Asia Minor and the Turanian Steppes, 



K 



