CHAP. XVII RORXEO AND JAVA 381 



animals, and gives us confidence in the results we may 

 arrive at in those cases where we have, from whatever 

 cause, to depend on a knowledge of the birds alone. And 

 if we consider the wide range of certain grouj)s of powerful 

 flight — as the birds of prey, the swallows and swifts, the 

 king-crows, and some others, we shall be forced to con- 

 clude that the majority of forest-birds are restricted . by 

 even narrow watery barriers, to an even greater extent 

 than mammalia. 



The Affinities of the Bornean Fauna. — The animals of 

 Borneo exhibit an almost perfect identity in general 

 character, and a close similarity in species, with those of 

 Sumatra and the Malay Peninsula. So great is this 

 resemblance that it is a question whether it might not be 

 quite as great were the whole united ; for the extreme 

 points of Borneo and Sumatra are 1,500 miles apart — as 

 far as from Madrid to Constantinople, or from the Missouri 

 valley to California. In such an extent of country we 

 always meet with some local species, and representative 

 forms, so that we hardly require any great lapse of time as 

 an element in the production of the peculiarities we actually 

 find. So far as the forms of life are concerned, Borneo, as 

 an island, may be no older than Great Britain; for the 

 time that has elapsed since the glacial epoch would be 

 amply sufficient to produce such a redistribution of the 

 species, consequent on their mutual relations being dis- 

 turbed, as would bring the islands into their present 

 zoological condition. There are, however, other facts to be 

 considered, which seem to imply much greater and more 

 complex revolutions than the recent separation of Borneo 

 from Sumatra and the Malay Peninsula, and that these 

 changes must have been spread over a considerable lapse 

 of time. In order to understand what these changes 

 probably were, we must give a brief sketch of the fauna of 

 Java, the peculiarities of which introduce a new element 

 into the question we have to discuss. 



