270 RISSOTD^. 



subeffuse at the base, angulate above ; peristome continuous, 

 thickened, duplicate. 



PROSOSTHENiA, Ncumayr. Shell small, ovate-conical or turreted, 

 longitudinally plicate ; last whorl coarctate, deflected ; aperture 

 ovate, oblique, entire ; peristome continuous, thickened, dupli- 

 cate, outer lip protracted. Tertiary ; Austria. P. Schwarzi, 

 ISTeum. (Ixxiii, 77). 



FOSSARULUS, Neumayr, Shell small, subglobose, rimate, with 

 revolving nodulous ribs, and longitudinal riblets ; aperture 

 widely ovate, effuse above and below ; peristome continuous, 

 thickened, duplicate. Tertiary; Austria. P. Stachei, Neum. 

 (Ixxiii, 78). 



Amnicola, Gould and Haldeman. 



Distr. — United States throughout, including California. A. 

 limosa, Say (Ixxiii, 79). 



Shell small, turbinately globose, thin, smooth, perforate or 

 iimbilicate ; aperture broadly ovate, not oblique, outer lip thin 

 and sharp, not projecting anteriorly. Operculum corneous. 



Foot rather short and broad, expanded and broadly rounded 

 behind ; rostrum short ; tentacles cylindrical, blunt at their tips. 

 Ova-capsules semilenticular, with a laminiform limb, each con- 

 taining a single egg. 



ToxosoMA, Conrad. 



Distr. — Tertiary ; So. America. T. eborea, Conr. (Ixxiii, 1 ). 



Shell conical, polished, the aperture projecting, subovate, 

 direct ; peristome continuous. Columella concave, with a 

 plait or tooth in the middle, not oblique ; base rounded, subum- 

 bilicated. Mr. Conrad supposed this to be a land-shell; its 

 position in the system cannot be accurately defined. 



LiosoMA, Conrad. 

 Distr. — Tertiary; So. America. L. curta^ Conr. (Ixxiii, 2). 

 Conical, polished ; aperture subelliptical ; cohtmella with one 

 plait in the middle ; base entire. Position very doubtful. 



Subfamily LITHOGLYPHINJE. 



Shell small, globose, spire short, last whorl proportionally very 

 large ; lip sharp. Fresh water. 



LiTiiOGLYPHUs, Muhlfeldt. 



Distr. — Fresh water. So. E. Europe, So. America. L. lapi- 

 dum, d'Orb. (Ixxiii, 80, 81 ). 



Shell globular, thick, smooth, imperforate; spire short; suture 

 not impressed ; aperture broadly subovate or nearlj^ circular, 

 inner lip callous, outer lip simple. Operculum corneous, 

 rounded. 



