xiv DISTRIBUTION 589 



only Australian but also Polynesian and South American affinities. 

 Some of the Birds are represented by the same or closely allied 

 species in New Caledonia, while the land Molluscs and Insects, 

 the Fresh-water Lamprey (G-eotria), and the Earthworms show 

 South American affinities. Still more remarkable is the fact 

 that a little fresh-water Fish, Galaxias attenuatus, occurs not 

 only in New Zealand and Tasmania, but in the southern extremity 

 of South America and in the Falkland Islands. In this con- 

 nection it is interesting to find that there is a submerged bank 

 of less depth than the surrounding ocean under 2,000 fathoms- 

 passing westwards from South America, and including many of 

 the Pacific Islands ; and an area, also of less than 2,000 fathoms, 

 in the Antarctic Ocean, sending offshoots northwards. The first 

 of these may possibly indicate a former westward extension of 

 South America, the second a former Antarctic land-area, perhaps 

 more or less directly connected with the existing southern conti- 

 nents. The whole question is quite unsettled and extremely 

 obscure, and is complicated by the fact that in one respect the 

 New Zealand fauna shows Ethiopian affinities. There have lately 

 been discovered in the Chatham Islands, a small group about 400 

 miles to the east of New Zealand, the remains of a long-beaked 

 Rail (Diaphorapteryx), evidently not long extinct, the nearest ally 

 of which is the Ked Bird (ApJianapteryx) of Mauritius, known to 

 have been exterminated by human agency. Moreover, the great 

 Ratite Birds, the ^Epyornithidae, of Madagascar, show undoubted 

 affinities with the Dinornithidse. 



The foregoing comparison of the faunas of Great Britain and 

 New Zealand leads us to the consideration of certain fundamental 

 conceptions of zoo-geography. 



Insular Faunas.- -We notice in the first place the striking con- 

 trast between the fauna of an island which has been recently 

 detached from a great continental area, and that of an island 

 which has remained isolated for an immense and unknown period. 

 In the one case the fauna has a strictly continental character, 

 there having been insufficient time for modification since the sepa- 

 ration took place. In the other case immigration has taken place 

 from various sources over a vast period of time, during which 



modification has taken place to a sufficient extent to give rise to 



j 



new or endemic species. 



Habitat, Range, and Station. Each kind of animal has, as 

 a rule, its own habitat, fresh-water in one case, the sea between 

 tide-marks in another, marsh, forest, snow-clad peaks, and so on. A 

 similar habitat may characterise whole genera and even orders. 

 Keeping always to its own habitat, the range of an animal may 

 extend over a vast area. The marsh-loving Curlew, for instance, 

 is found all over the world : the Cormorants (Phalacrocorax), Gulls, 



