PHYSA HYPNORUM. 37 



JIplexa hypnorum, Fleming. Moll. An., p. 158. 

 JIplexus hypnorum, Gray's Turton, p. 255, fig. 113. 



DESCRIPTION. 



Animal "deep black, immaculate above and 

 beneath: tentacula setaceous, a white annula- 

 tion at base." — Say. 



Shell slender, translucent, and highly polish- 

 ed; composed of five or six obliquely revolving, 

 flattened whirls: apex apparently acute, but 

 when closely examined, will be found to be con- 

 vex: aperture narrow, obtusely rounded ante- 

 riorly, acute posteriorly; labium scarcely appa- 

 rent; columellar fold very slight. 



Color ochre-yellow, or light yellowish-brown, 

 sometimes presenting violet and green prismatic 

 reflexions: columella sometimes rose-coloured. 



Geographical Distribution. Inhabits Mas- 

 sachusetts, Vermont, New York, and the West- 

 ern States, "stagnant ponds on the banks of 

 the Mississippi." — Say. "Saskatchewan." — 

 Dr. Richardson. Figures 7 — 9 were brought 

 from Lewis' river, Oregon, by Mr. Nuttall. 



OBSERVATIONS. 



"When the shell includes the animal, it ap- 



