3l6 CHINA CHAP. 



(2) The Chinese Sub-region. — The Chinese Sub-region m.- 

 clucles the whole of China from its southern frontier up to and 

 including the basin of the Blue or Yang-tse River, together with 

 the coast district, including Corea, perhaps as far north as Vladi- 

 vostok, and the outlying islands of Hainan, Formosa, the Loo- 

 Choo and Bonin groups, and Japan to the north of Niphon. It 

 may be divided into two provinces, the Chinese and the Japanese, 

 (rt) The fauna of the Chinese province proper bears, in many 

 respects, strong marks of relationship to that of India and Siam. 

 Thus Streptaxis^ Helicarion^ Macro chlamys^ Kaliella^ Sitala^ Ario- 

 phanta^ Rhysota^ Heiniplecta^ Diplommatbia^ Opisthoporus. Ptero- 

 cyclus, Lagocliilus^ and Alycaeus all occur, especially in Southern 

 China. The two points in which the sub-region bears special 

 marks of individuality are Helix and Clausilia. The sub-genera 

 of Helix which have their metropolis in China are Satsuma, 

 Cathaiea^ Aegista^ Acusta., JEuhadra^ Pleetotropis^ and Plectopylis. 

 Sinistral forms (compare Fig. 213) are rather prevalent. In 

 several cases — e.g. Trichia Gonostoma Fruticicola — there is a 

 reappearance of forms which appear to belong to well-known 

 European sub-genera. Clausilia here attains a kind of second 

 centre of distribution, and is represented by its finest forms, 



which belong to several peculiar 

 sub-genera. The carnivorous Mol- 

 lusca are not abundant, and are rep- 

 resented by Rathouisia (a peculiar 

 genus of naked slug), Hnnea, and 

 Streptaxis. In the western provinces 

 Buliminus is abundant in several 

 Yig.iiz.— Helix iCamaena) cica- sub-genera, One of which appears to 

 tricosa MiiiL, China. be the European Napaeus. 



There is little which is striking in the operculates, which are 

 most abundant in the south, and appear to be mainly derived 

 from Indian and Siamese sources. The occurrence of Helicina 

 (3 sp.), Omplialotropis (1), Leptopoma (2), and Realia (2), is 

 evidence of some influence from the far East. Heudeia is a 

 very remarkable and quite peculiar form of Helicina Avith 

 internal plicae, perhaps akin to the Central American Ceres. 



Fresh-water genera are exceedingly abundant, especially 

 Melayiia^ Unio^ and Anodonta. The occurrence of Mycetopus 

 (a South- American genus) is remarkable. There are several 



