LIMNEA COLUMELLA. 39 



L. MACROSTOMA, GouLD. Invert, of Mass., p. 217, fig. 



148. 

 L. coARCTATA, Lea. Proceed, of Am. Phil. Sec, vol. 



2, p. 33. 



DESCRIPTION. 



Shell ventricose, ovate, fragile, thin in tex- 

 ture, and diaphanous: suture impressed and con- 

 spicuous: whirls 4, with the lines of accretion 

 apparent, and crossed by minute spiral striae: 

 spire narrow, acute, and much shorter than the 

 aperture: aperture very large, more or less 

 expanded; labium a thin film of enamel, not 

 quite appressed anteriorly; peritreme extremely 

 thin and fragile, entering the axis, and forming 

 an open spiral, of which two or three turns are 

 generally visible. 



Color hght straw yellow, frequently tinged 

 greenish, brown, or black, by foreign matter. 



Geographical Distribution. Maine, Massa- 

 chusetts, Pennsylvania, Ohio, South Carolina, 

 the North-west Territory, and Lake Winnipeg. 



Foreign Analogue. L. ovata. 



OBSERVATIONS. 



The labium is sometimes scarcely visible, 



