1920.] N. Annandai,e : Indian Hydrohiidae. 43 



Morelet; B. stenothyroides, Dohrn; B. dihrugarhensis, 

 Preston; Amnicola alticola, Annandale. 



To Bithynia, Leach, the following : — 



B. tentaculata (Linne), the type-species ; B. cerameopoma 

 (Benson) ; B. pulchella (Benson) ; B. lutea, (jx^y ; B. Pyg- 

 maea, Preston ; B. iroscheli (Paasch). 



To Hydrobioides, Nevill : — 



B. turrita, Blanford, the type-species ; B. nassa, Theobald ; 

 B. moreletiana, Nevill; Hydrobioides nana, Annandale; 

 H. avarix, Annandale. 



To Saiaria, gen. nov. : — 



Bithynia evezardi, Blanford, the only known species. 



To Mysorella, God win- Austen : — 



Bithynia cosiigera (Kiister) with its race curta, Nevill, 

 which is the type of the genus. 



All these species occur within the limits of the Indian Empire, 

 but B. tentaculata and B. troscheli are Palaearctic and are only 

 found, so far as India is concerned, in Kashmir and the neighbour- 

 ing country, while Hydrobioides seems to be exclusivel}^ Burmese ; 

 Mysorella is confined to the southern part of Peninsular India 

 (plains and Mysore Plateau) and Ceylon, and Sataria to the Bombay 

 section of the Western Ghats. The range of Alocinma extends 

 from Mesopotamia to Upper Burma, and the south of the Indian 

 Peninsula, but the subgenus is closely allied to the Palaearctic 

 Pseudamnicola, which may also be regarded as a subgenus of 

 Amnicola. Amnicola {s.s.) is American. Si^^3'ni« is found all over 

 Europe and Asia, but is perhaps mainly Palaearctic. 



Subfamily BITHYNIINAE. 

 Genus Amnicola, Gould and Haldeman (1841). 



1865. Ainm'cola, Simpson, Smiths. Misc. Coll. 201, p. 12. 



This genus, as has been pointed out recently, can be divided 

 into three subgenera, Amnicola, s.s. (American), Pseudamnicola 

 (Palaearctic) and Alocinma (Indian, Persian and Mesopotamian). 

 All the Indian species of the genus I have examined belong to it. 



Subgenus Alocinma, Annand, and Prashad (1919). 



igig. Alocinma, Annandale and Prashad, Rec. Ind. Mns. XVIII, p. 23. 



The shells of this subgenus are more or less globose, with the 

 whorls somewhat tumid, the body-whorl very large and the suture 

 rather wide. The umbilicus is almost or entirely closed and- the 

 columellar fold is never prominent though always ridge-like. There 

 is no well-defined groove proceeding downwards from the um- 

 bilicus outside the fold. The shell-sculpture is microscopic. The 



