CHINA, HAINAN, FORMOSA, AND COREA 



317 



peculiar forms of fresh-water operculates, whose exact position is 

 hardly yet assured. 



Land and Fresh-water Mollusca of the Chinese Province 



The island of Hainan, in the extreme south of the sub-region, 

 has 40 species of Mollusca, 22 of which are peculiar, but there is 

 no peculiar genus. 



The Mollusca of Formosa, although in many cases specifically 

 distinct, show close generic relationship with those of China. 

 The characteristic Chinese groups of Helix and Clausilia occur, 

 and there is still a considerable Indian element in several species 

 of Streptaxis, Macrochlamys, Kaliella, and Alycaeus. The oc- 

 currence of two Amphidromus, a genus which, though Siamese, 

 is not found in China or Hainan, is remarkable. 



The peninsula of Corea must undoubtedly be included in the 

 Chinese sub-region. It is true that the land operculates scarcely 

 occur, but there are still a number of Clausilia, and several of 

 the characteristic Chinese groups of Helix are reproduced. In 

 some points Corea appears to show more affinity to Japan than 



