ig2i.] Manipiir Molluscs. 543 



tip. It projects outwards towards the left at a right angle and 

 originates near the base of the inner side of the penis. 



Type-series. — No. 1 1860/2 Zool. Surv. Ind. {Ind. Mus.) 

 Habitat. — The species is abundant and generally distributed 

 in the Manipur valley, outside which it has not been found. It 

 lives in small sluggish streams, pools and swamps in the plains but 

 was not found in the lyoktak Lake. It crawls slowly on the lower 

 surface of floating grass-stems and water-weeds and can float 

 shell downwards on the lower side of the surface film. It is resist- 

 ant to drought, and individuals brought dry to Calcutta revived 

 on being placed in water after over a fortnight's desiccation. The 

 shell is usually covered with mud. 



Affinities, etc. — As in most Indian species of the genus the 

 shell is somewhat variable in shape and the spire is more produced 

 in some individuals than in others. In the majority, however, it is 

 relatively short and has a rather close resemblance in general out- 

 lines to some species of .Hocinma. In sculpture it closely re- 

 sembles A . travancorica (Benson). The structure ot the aperture and 

 the adjacent parts is, however, eminently characteristic of Digonios- 

 toina and the operculum, though like that of Hydvobioides nassa it 

 shows traces externally of a spiral origin in the nuclear region, is 

 much less spiral than in Alocinma. I am not acquainted with any 

 species to which D. textitm is closely related. 



Family VIVIPARIDAE. 



This family may almost be called the dominant one among 

 the Gastropods of the Manipur valley, for not only are individuals 

 extremely abundant, but the two commonest species attain a size 

 quite exceptional. Four species are represented in our collection, 

 of which two are rare, while two occur in all suitable bodies of 

 water in very large numbers. 



Vivipara, JMontfort. 



19211. Vii'ipava, Annandale, Rec. Ind. Mus. Xl.X, p. 112. 



In the paper cited I have separated the Indian species of 

 this genus into four groups, the Viviparae bengalenses, the Vivi- 

 parae oxytropides, the Viviparae dissimiles^ and the Viviparae 

 sindicae. With the exception of the last, each of these groups 

 is represented in the Manipur fauna by one species and all but one 

 (F. oxytropis) of these species are apparently endemic. 



Viviparae bengalenses. 



This group has as its Manipur representative a hitherto un- 

 described species quite distinct from both V. bengalcnsis (Lamarck), 

 the races and phases of which are scattered over most parts of 

 the Indian Empire, and V. nagaensis, Preston, which is known only 

 from the Naga Hills. For this new species I propose the name : — 



