252 CONCHYLI A— D/Ti/Yi?^. 56 



Turton, Linn. Syst. iv. p. 187. 

 Wood, Conch, p. J 52. 

 Dillwyn, Descript. Catal. p. 106. 

 Mus. nost. In slow streams and stagnant ponds. 



Shell about the eighth of an inch long, and a little broader ; very 

 convex thin and transparent, horn-color or yellowish, often covered 

 with a rough coat, with obscure close-set transverse striae : beaks 

 near one end, not tumid as in the last species. 



From the young of Cyclas amnica it is distinguished by its greater 

 convexity, and the want of regular grooves between the raised striae : 

 and from the other species by its oblique outline, not having the 

 beaks central. 



