2*72 ASSIMINTID^. 



Lacunopsis, Desh. 



Distr. — 3 sp Cambodia. Fresh water. L. Jullieni, Desh. 

 (Ixxiii, 89). 



Shell depressed, solid, neritiform ; base plane, with a sub- 

 marginal angle ; aperture small, semilunar ; lip and columella 

 greatly thickened. 



SPEKTA, BourgTiignat, 1881. Growth-lines oblique, crossed at 

 right-angles by striae ; a small obsolete funicule behind the colu- 

 mellar lip. L. zonata, Woodward (Ixxiii, 90, 91). L. Tangan- 

 yika, Africa. 



Subfamily POMA TIOPSIN^. 



Shell and operculum as in Rissoinse. Foot with lateral sinus. 

 Amphibious. 



PoMATiopsis, Tryon. 



Syn. — Chilocyclus, Gill. 



Distr. — United States, Central America. P. lapidaria, Say 

 (Ixxiii, 92), 



Shell elongated, perforate, smooth, whorls very convex; aper- 

 ture round ; peristome continuous, slightly expanded or reflected. 



The animal of Pomatiopsis prefers damp locations in the 

 vicinity of streams, but does not, like Amnicola, live habitually 

 under water. It is an air-breather, but possessed of a true gill. 

 Its locomotion is effected by first protruding and attaching the 

 snout, then carrying the front of the body forward, and finally 

 drawing the posterior parts after, a motion very like that of 

 Assiminea and very diflf'erent from Amnicola. 



Family ASSIMINIID^. 



Shell small, globose-conical, with sharp lip. Operculum pauci- 

 spiral, corneous. 



Animal with eyes at or near the ends of the tentacles as in 

 the helices. 



Terrestrial or amphibious. 



Assiminea, Leach, 



Syn. — Syncera, Gray. Optediceras, Leith. Hydrocena, in 

 part. 



Distr. — Europe, Asia, America, a few species. A. Graya,na, 

 Leach (Ixxiii, 93). 



Shell not perforated or slightly slit, oval-conic, with moderate 

 spire ; aperture rounded-oval, entire ; columellar lip somewhat 

 thickened. Animal, Tentacles rather short, the eye-peduncles 

 connate with them to their ends. The Indian species, A. Fran- 

 cesiee, can often be seen for days together on dry land, walking 

 or rather leaping with great rapidity like a caterpillar of the 



