32 



ISLAND LIFE 



PART I 



perhaps not that of half-a-dozen species. Either they 

 range into Siberia, or Asia Minor, or Palestine, or North 

 Africa ; and this seems to be always the case when their 

 area of distribution occupies a large portion of Europe. 

 There are, indeed, a few species limited to Central or 

 Western or Southern Europe, and these are almost the 

 only cases in which we can use the word for zoological 

 purposes without having to add to it some portion of 

 another continent. Still less useful is the term Asia for 

 this purpose, since there is probably no single animal or 

 group confined to Asia which is not also more or less 

 nearly confined to the tropical or the temperate portion of 

 it. The only exception is perhaps the tiger, which may 

 really be called an Asiatic animal, as it occupies nearly 

 two-thirds of the continent ; but this is an unique example, 

 while the cases in which Asiatic animals and groups are 

 strictly limited to a portion of Asi^i, or extend also into 

 Europe or into Africa or to the Malay Islands, are exceed- 

 ingly numerous. So, in Africa, very few groups of animals 

 range over the whole of it without going beyond either 

 into Europe or Asia Minor or Arabia, while those which 

 are purely African are generally confined to the portion 

 south of the tropic of Cancer. Australia and America are 

 terms which better serve the purpose of the zoologist. 

 The former defines the limit of many important groups of 

 animals ; and the same may be said of the latter, but the 

 division into North and South America introduces 

 difficulties, for almost all the groups especially character- 

 istic of South America are found also beyond the isthmus 

 of Panama, in what is geographically part of the northern 

 continent. 



It being thus clear that the old and popular divisions 

 of the globe are very inconvenient when used to describe 

 the range of animals, we are naturally led to ask whether 

 any other division can be made w^hich will be more useful, 

 and will serve to group together a considerable number of 

 the facts we have to deal with. Such a division was made 

 by Mr. P. L. Sclater more than twenty years ago, and it 

 has, with some slight modifications, come into pretty 

 general use in this country, and to some extent also 



