300 THE ORIENTAL REGION chap. 



In this vast extent of land two distinct centres of influence 

 are prominent — the Indian and the Chinese. Each is of marked 

 individuality, but they differ in this essential point, that while 

 the Chinese element is decidedly restricted in area, being, in 

 fact, more or less confined to China itself and the adjacent 

 islands, the Indian element, on the other hand, extends far be- 

 yond continental Asia, and embraces all the Malay islands to 

 their farthest eastward extent, until it becomes overpowered by 

 the Papuan and Australian fauna. Upper Burmah, with Siam, 

 forms a sort of meeting-point of the two elements, which here 

 intermingle in such a way that no very definite line of demarca- 

 tion can be drawn between them. 



Thus we have — 



Oriental Region 



f (a) Indian Province 



-1 r 7 71^ 7 o 7 Ti • ' (^) Siamese Province 

 ^ 1. Indo-Malay Sub-Region j ^^^ ^^^^^ p^,^^.^^^^ 



L (d) Philippine Province 



o ^z. • e ^ r» • / (^) Chinese Province 



2. Chinese Sub-Regwn | ^^^ Japanese Province 



The Indo-Malay fauna spreads eastward from its metropolis, 

 but has practically no westward extension, or only such as may 

 be traced on the eastern coasts of Africa and the off-lying 

 islands. There appears to exist no other case in the world 

 where the metropolis of a fauna is so plainly indicated, or where 

 it lies, not near the centre, but at one of the ends of the whole 

 area of distribution. 



Comparing the two sub-regions, the Chinese is distinguished 

 by the great predominance of Helix, while in the Indo-Malay 

 sub-region Nanina and the related genera are in the ascendancy. 

 In India itself there are only 6 genera of true Helicidae, poorly 

 represented in point of numbers ; in China there are at least 

 three times this amount, most of them abundant in species. 

 The Indo-Malay sub-region, on the other hand, is the metropolis 

 of the Naninidae, which abound both in genera and species. In 

 the Chinese sub-region Clausilia attains a development almost 

 rivalling that of S.E. Europe, while in India there are scarcely 

 a dozen species. A marked feature of the Indo-Malay sub-region 

 is the singular group of tubed land operculates (^Opisthoporus^ 

 Pteroci/elus, etc.). In China the group is only represented by 

 stragglers of Indian derivation, while the land operculate fauna. 



