CHAPTER VIII. 



THE ORIENTAL REGION. 



Sub-regions Characteristics of the Mammalian Fauna Past History of the 

 Region Malayan sub-region Nicobars, Mentawi, and Christmas Islands 

 Philippine sub-region. 



FAR inferior in extent to the Ethiopian, the Oriental region is 

 taken to include those portions of the continent of Asia lying 

 south of the Holarctic region (with the exception of southern 

 Arabia, which is Ethiopian), together with the islands of Ceylon, 

 Formosa, the Philippines, Sumatra, Java, Borneo, and numerous 

 smaller ones. In India the northern limits of the region are 

 formed by the higher ranges of the Himalaya, while " Wallace's 

 line" constitutes the eastern boundary denning it from the Austro- 

 Malayan region of the Notogaeic realm. In a region so diversified 

 as the Oriental, it would not be natural to expect a homogeneous 

 fauna; and, as a matter of fact, there are in this respect great 

 diversities between the different portions of the region, many of 

 the peculiar genera having a very restricted distribution. Never- 

 theless, the positive and negative features of the mammalian fauna 

 of the region as a whole are sufficient to indicate its zoological 

 unity, and also to differentiate it from the Ethiopian region, to 

 which it is now most closely allied. In the Himalaya there is a 

 gradual transition towards the Holarctic fauna ; and it is probable 

 that in this portion of the area the differentiation between the 

 Oriental and Holarctic faunas has been largely due to the eleva- 

 tion of the Himalaya itself, which has taken place entirely since 

 the early part of the Tertiary period, and is to a considerable 

 extent of Post-tertiary date. It has already been shown that the 

 older Pliocene fauna of northern India and Burma contained a 



