LIMNEA EMARGINATA. 11 



DESCRIPTION. 



Shell ovate-conic, thin in texture, translu- 

 cent, and smooth; having the lines of growth 

 very fine: there are five whirls, which are very 

 convex, and are separated by a deep suture: 

 apex, when present, acute: aperture wide, and 

 more than half the entire length: labium turned 

 over, so as to form an umbilic: fold on the 

 columella obsolete: columellar depression deep- 

 ly emarginate. 



Color light ochraceous. 



Geographical Distribution. Inhabits "lake 

 Namakin, north of lake Superior" — Say: lakes 

 in the North-west Territory, — Mr. Taylor: and 

 the State of Maine, — Dr. Gould. 



OBSERVATIONS. 



"This species is rather larger, and consider- 

 ably wider than L. catascopium; and the emar- 

 gination visible on a profile view of the um- 

 bilical groove, is far more profound." — Say. 



Specimens are not common in collections, so 

 that it is difficult to define the limits of the 

 species. Thus figure 1 differs considerably 

 from figure 6, but they both agree in having a 



