3l6 CHINA CHAP. 



(2) The Chinese Sub-region. — The Chinese Huh-rrgion in- 

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

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

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

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

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

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

 (rt) The fauna of the Chinese 'ji'^'ovince jyroper bears, in many 

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

 Thus Streptaxis, Helicarion, Macrochkunys, Kaliella, Sitala, Ario- 

 phanta, Rhysota, Hemiplecta, Dip)lommatina, Opistlioporus, Ptero- 

 cyclus, LagocliiJus, and Alycacns all occur, especially in Southern 

 China. The two points in which the suli-region l)ears special 

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

 of Helix which have their metropolis in China are Satsuma, 

 Cathaica, Aegista, Acusta, Euhaclra, Flectotropis, and Flectopylis. 

 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 distril)ution, and is represented by its finest forms, 



which belong to several peculiar 

 sul)-s;enera. The carnivorous Mol- 

 lusca are not abundant, and are 

 represented by Rathouisia (a peculiar 

 genus of naked slug), Ennca, and 

 Streptaxis. In the western provinces 

 Bnliminus is abundant in several 

 YiG. 2lZ.— Helix {Ca mama) cica- sub-gcnera, one of which appears to 

 tricosa Miill., China. ^^^ ^.^^^ 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.), Omphalotropis (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 with internal 

 plicae, perhaps akin to the Central American Ceres. 



Fresh - water genera are exceedingly abundant, especially 

 Melania, Unio, and Anoclonta. The occurrence of Mycetopus 

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



