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 

 imperfectly known ; indeed, it is only at a few points that any- 

 thing 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 Palaearctic 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 Corhicula and 

 Melania occm'S, but is not sufficient to disturl) 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 principal 

 features in the land Mollusca appear to be the occiu'rence of a 

 number of Buliminus of the JVapaeus group, a few Farmacella 

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

 Pupa, Limax, and Helix, witli several stray species of Macro- 

 chlamys. 



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. 



