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 



Rathouisia . . 



1 



Trichia . . 



. 10 



Succinea . . 



8 



Leptopoma . , 



2 



Streptaxis . . 



7 



Cathaica 



. 22 



Vaginula . . 



7 



Lagochilus . . 



10 



Ennea . . . 



12 



Aegista . . 



. 10 



Limnaea . . 



2 



Cyclophorus . 



18 



Parmarion . . 



2 



Armandia . 



. 3 



Planorbis . . 



6 



Coelopoma . . 



1 



Helicarion . . 



15 



Acusta . . 



. 15 



Melania . . . 



44 



Pterocyclus 



3 



Euplecta . . 



3 



Obbina . . 



. 1 



Paludomus 



3 



Opisthoporus . 



4 



Macrochlamys 



19 



Camaena . 



. 5 



Bithynia . . 



12 



Cyclotus . . 



10 



Microcystina . 



2 



Euhadra . 



. 14 



Lithoglyphus . 



3 



Scabrina . . 



4 



Microcystis 



7 



Plectopylis . 



. 19 



Melantho (?) . 



1 



Ptychopoma . 



12 



KalieUa. . . 



16 



Stegodera . 



. 6 



Pachydrobia . 



1 



Omphalotropis 



1 



Sitala . . . 



8 



Chloritis . 



. 1 



Prososthenia . 



2 



Realia . . . 



2 



Ariophanta 



1 



Hel. Inc. sed. 



. 39 



Stenothyra . . 



2 



Pseudopomatias 1 



Rhysota . . . 



5 



Buliminus . 



. 21 



Hydrobia . . 



2 



Helicina . . . 



3 



Hemiplecta 



1 



Buliminopsis 



. 3 



Mecongia . . 



1 



Georissa . . . 



4 



Trochomorpha 



2 



Buliminidius 



. 3 



Oncomelania . 



9 



Heudeia . . . 



1 



Limax . . . 



1 



Napaeus 



. 14 



Margaracya . 



1 



Cyclas . . . 



1 



Philomycus . 



1 



Rachis (?) . 



. 4 



Rivularia . . 



4 



Corbicula . . 



50 



Patula . . . 



2 



Pupa . . 



. 10 



Delavaya . . 



1 



Unio .... 



53 



Gonostoma . . 



4 



Clausilia . 



102 



Eenouillia . . 



1 



Monocondylaea 



1 



Metodontia . 



2 



Opeas . . 



. 12 



Vivipara . . 



34 



Anodonta . . 



55 



Vallonia . . 



1 



Euspiraxis . 



. 1 



Diplommatina 



20 



Mycetopus . . 



12 



Plectotropis . 



9 



Subulina . 



. 5 



Pupina . . . 



6 



Pseudodon . . 



1 



Friuicicola 



11 



Stenogyra (?) 



. 12 



Alycaeus . . 



23 



Dipsas . . . 



4 



Satsuma . . 



14 















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, KalieUa, 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 



