THE ORIENTAL REGION 141 



Section VI. — The Malayan Sub-region 



The Malayan Sub-region lies entirely within the tropics, 

 and almost the whole of it is covered with a luxuriant 

 tropical jungle. It is here, consequently, that we find the 

 Oriental fauna in its highest state of development, and with 

 the least admixture of forms belonsrmsr to other Regions. 

 With the exception of the Malay Peninsula, the whole of 

 this Sub-region consists of islands, which, however, are 

 separated from the main continental mass by comparatively 

 shallow water, so that an elevation of 100 fathoms would 

 obliterate the whole of the sea between the various islands, 

 leaving them connected with one another and with the 

 Asiatic continent. There can be no doubt that these islands, 

 all of which have very rich faunas, have been stocked from 

 the mainland, and that a careful study and comparison of 

 their component parts would go far to enable us to trace 

 out the past history of the Region, and to find out what 

 changes have taken place from time to time in the distri- 

 bution of land and sea. 



If a careful analysis of the mammalian genera of the 

 Sub-region be made, it will be found that the greater 

 number of the genera found on the mainland extend to 

 all the three larger islands, Sumatra, Java, and Borneo, and 

 that of the remaining genera the larger proportion are 

 common to the Malay Peninsula, Sumatra, and Borneo, 

 and are not found in Java. This would seem to indicate 

 that Java was separated from the mainland before Sumatra 

 and Borneo, and this view is further borne out by the 

 fact that individual species of a genus are frequently 

 common to the Malay Peninsula, Sumatra, and Borneo, 



