CENTRAL ASIA 



299 



are purely oceanic, and have been colonised from the western 

 coasts of the Mediterranean, i.e. from the direction of the prevail- 

 ing currents and winds. 



(3) Central- Asiatic Sub-region. — The countries included 

 in this vast sub-region are Turkestan, Songaria, Afghanistan, 

 including the Pamirs, Western Thibet, and probably Mongolia. 

 Kashmir belongs to the Indian fauna. At present the whole 

 district is very impei'fectly known ; indeed, it is only at a few 

 points that anything like a thorough investigation of the fauna 

 has been made. It is therefore almost premature to pronounce 

 any decided opinion upon the Mollusca, but all the evidence at 

 present to hand tends to show that they belong to the Palae- 

 arctic and not to the Oriental system. This is especially the 

 case with regard to the fresh-water Mollusca, many of which 

 are specifically identical with those occurring in our own islands. 

 A slight admixture of such widely distributed types as Corbicida 

 and Melcmia occurs, but it is not sufficient to disturb the general 

 European facies of the whole. It is possible that eventually 

 the whole district may be regarded as a sub-region combining 

 certain characteristics of the eastern portions of the Mediter- 

 ranean basin with an extension of the septentrional element, 

 due to higher elevation and more rigorous climate. The prin- 

 cipal features in the land Mollusca appear to be the occurrence 

 of a number of Bidiminus of the Napaeus group, a few Parma- 

 cella (Afghanistan being the limit of the genus eastward), 

 Clausilia^ Pupa., Limax., and Helix^ with several stray species of 

 Macrochlamys. 



B. The Oriental or Palaeotropical Region 



This region includes all Asia to the south of the boundary 

 of the Palaearctic region, that is to say, India, with Ceylon, 

 Burmah, Siam, and the whole of the Malay Peninsula, China 

 proper, with Hainan and Formosa, and Japan south of Yesso. 

 It also includes the Andamans and Nicobars, and the whole of 

 Malaysia, with the Philippines, as far eastward as, and includ- 

 ing Celebes with the Xulla Is., and the string of islands south 

 of the Banda Sea up to the Ke Is. The Moluccas, in their two 

 groups, are intermediate between the Oriental and Australasian 

 regions. 



