o62 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



Insular or u Malayan n Province. The northern boundary of the 

 Insular Province is not at present easily determinate, but it is quite 

 evident that, as already stated, the southern maritime portions of 

 Indo-China belong here rather than with the northern 'division of the In- 

 dian Eegion. To the southward and eastward it embraces, as already 

 explained, the Sunda Islands, the Philippines, and Celebes. Of the 

 eighty-three genera occurring in it, twenty-five, or nearly one fourth, are 

 peculiar, while twenty-seven others do not range beyond the Indian 

 Province. Twenty of the remainder are properly Indo-African genera, 

 while about a dozen others have a wide extralimital range, and about 

 the same number have a very local range, the larger islands having 

 each one or two peculiar genera. Aside iroin several tropicopolitan 

 genera of Bats, and the wide-ranging genera Sus and Mus, only one 

 genus is properly Australian, and this is a straggler that merely reaches 

 Timor and Celebes. As would be expected, the larger central islands, 

 together with Malacca and the mainland belt, possess the richest and 

 most varied fauna, the smaller outlying islands presenting a paucity of 

 types proportionate to their size and isolation. 



Timor, considering its close proximity to Australia, is remarkably 

 free from Australian forms, presenting, in common with Celebes, the 

 single Marsupial genus Cuscus. The distribution of the genera of this 

 province is roughly indicated in the subjoined table. Notwithstanding 

 its much smaller land-area, and the fact that it has ten less genera than 

 the Continental Province, it has, as would be naturally expected, many 

 more peculiar genera,* the ratio of peculiar genera in the one being as 

 16 to 94, and in the other as 25 to 83. 



* Four, however, are peculiar only in regard to the Indian Region, they being simply 

 wide-ranging tropical forms that are unrepresented in the Continental Province. 



