8 LIMNEA CATASCOPIUM. 



GEOGRAPHICAL DISTRIBUTION. Inhabits Mas- 

 sachusetts, Earle's catalogue: New York, near 

 Niagara Falls, Dr. W. Blanding: the Hudson, 

 Dr. Gould: the Northwest Territory, Mr. Tay- 

 lor: from 'Canada to Saskatchewan:' and the 

 Delaware. 



VAR. L. PINGUIS. The Northwest Territory, 

 (fig. 9, Mr. R. C. Taylor,) and the Delaware 

 (fig. 810,) and Schuylkill rivers. Mr. Nut- 

 tall has given me specimens from Lewis' river, 

 Oregon; which, though considerably larger, 

 appear to belong to this variety. 



OBSERVATIONS. 



I have thought it best to unite two of Say's 

 proposed species, for the separation of which 

 I think there are not sufficient grounds. My 

 suite of specimens is not sufficiently extensive 

 to demonstrate the identity of the two; but 

 I think the original shells of my figures 6 and 

 10 12, have too near a resemblance to allow 

 them to be separated as distinct species. 



The variety differs in having a shorter spire, 

 and the turns composing it more inflated; 

 whilst the apex is not as much attenuated as 

 in L. catascopium. 



