174 
MB. A. E. WALLACE ON THE ZOOLOGICAL 
(only 35 miles wide) marks the limits and abruptly separates two 
of the great Zoological regions of the globe. The Philippine 
Islands are in some respects of doubtful location, resembling and 
differing from both regions. They are deficient in the varied 
Mammals of Borneo, but they contain no Marsupials. The Psittaci 
are scarce, as in the Indian region ; the Lories are altogether ab- 
sent, but there is one representative of the Cockatoos. 'Woodpeckers, 
Trogons, and the genera Ixos, Copsychus , and Ploceus are highly 
characteristic of India. Tanysiptera and Megapodius, again, are 
Australian forms, but these seem represented by only solitary 
species. The islands possess also a few peculiar genera. We 
must on the whole place the Philippine Islands in the Indian region, 
but with the remark that they are deficient in some of its most 
striking features. They possess several isolated forms of the Au- 
stralian region, but by no means sufficient to constitute a real 
transition thereto. 
Leaving the Philippines out of the question for the present, the 
western and eastern islands of the Archipelago, as here divided, 
belong to regions more distinct and contrasted than any other of the 
great zoological divisions of the globe. South America and Africa, 
separated by the Atlantic, do not differ so widely as Asia and 
Australia : Asia with its abundance and variety of large Mammals 
and no Marsupials, and Australia with scarcely anything but 
Marsupials; Asia with its gorgeous Phasianidce, Australia with 
its dull-coloured Megapodiidce ; Asia the poorest tropical region 
in Parrots, Australia the richest : and all these striking charac- 
teristics are almost unimpaired at the very limits of their respective 
districts ; so that in a few hours we may experience an amount of 
zoological difference which only weeks or even months of travel 
will give us in any other part of the world ! 
Moreover there is nothing in the aspect or physical character of 
the islands to lead us to expect such a difference ; their physical 
and geological differences do not coincide with the zoological 
differences. There is a striking homogeneity in the two halves 
of the Archipelago. The great volcanic chain runs through both 
parts ; Borneo is the counterpart of New Guinea ; the Philip- 
pines closely resemble the equally fertile and equally volcanic 
Moluccas ; while in eastern Java begins to be felt the more arid 
climate of Timor and Australia. But these resemblances are 
accompanied by an extreme zoological diversity, the Asiatic and 
Australian regions finding in Borneo and New Guinea respectively 
their highest development. 
