4 Records of the Indian Museum. [Vor.. XXII, 



Full}' formed shells of this genus are easily distinguished from 

 those of Biihynia by their thickened lip and much broader and 

 flatter columellar margin. The channel leading from the umbilicus 

 is also practicall}' absent. 



The type-species is Fairbankia ? (an Biihyma ?) turrita, Blan- 

 ford, a form with a very narrow elongate shell. The genus is 

 Burmese. Mr. Kennard tells us that he has seen a fossil (tertiary) 

 species from the L,oess of I,ei Chung, west of Shun L,e-fu, N. China. 



Genus Paranerita, Annandale (1920). 



1920. Paraneyiia f^subgenus of Hvdrobioides), Annandale, op. cit., p. 



J-S- 



The structure of the animal and operculum in P. physcus, 



the only known species, is too close to that of Hvdrobioides to 



permit of its expulsion from the Bithyniinae, but that of the shell 



is perhaps too different to allow its retention in the genus. 



P. physcus is only known from the Shan Plateau in Upper 

 Burma. 



Genus Digoniostoma, Annandale (1920). 



1920. Biihynia (in part), Annandale, op. cit., p. 41. 



1920. Digoniostoma, Annandale, /nd. jFoiirii. Med. Res. (in the press). 



The shell of this genus differs from that of the true Biihynia 

 in the structure of the mouth. The lip is somewhat thickened, 

 though usually less so than in Hydrobioides, and more or less lami- 

 nate. It is produced and angulate at the inner lower extremity. 

 The columellar callus is broad and stout and as a rule distinctlj' 

 laminate, but not so flat as in Hydrobioides. Otherwise the two 

 genera are closely related. 



The type-species is Paludiva cerameopoma, Benson, a common 

 and widely distributed Indian mollusc. 



Genus Amnicola, Gould and Haldeman (1841). 



This genus is American and is distinguished from the other 

 Bithyniine genera by its horny, spiral operculum and by the pre- 

 sence of only a single denticulation on each side of the base of the 

 central tooth of the radula. Hutton's Paludina parvula ' must be 

 assigned to it provisionally as he says, "Operculum horny," and 

 Hanley and Theobald* say that the shell is that of an Amnicola; 

 but the species needs further investigation. It was found near 

 Chaman, which is now on the Northern Afghan frontier of Balu- 

 chistan, and is not represented in the collection of the Indian 

 Museum. Mr. G. C. Robson has kindly informed us that the oper- 

 cula are no longer present in the two specimens figured by Hanley 

 and Theobald, originally from Hanley's collection, and now pre- 

 served in the British Museum. 



1 Jotirn. As. Soc. Bengal, XVIII, p. 655, pi. ii (1849). 

 ■2 Conch. Ind., p. 61, pi. cli, figs. 8, 9 (1876). 



