336 Mighels' Catalogue of 



specimens from 2d Eagle Lake, Maine, in N. lat. 47°. In 

 one specimen, the spire is not elevated above the penultimate 

 whorl. 



P. hypjiorwn, Drap. (P. elongata, Say.) There can no 

 longer be a doubt as to the identity of this species. It occurs 

 at Monmouth, and in a swamp near Bangor. 



P. gyrina, Say. Mr. True has found this species at Mon- 

 mouth. Among some specimens received from him, I find 

 several that differ in no respect from P. osculans, Haldeman, 

 from Mexico, which appears to me to be nothing more than 

 an elongated variety of P. ancillaria. 



P. fragilis, Migh. Found at Monmouth by ^Mr. True. Be- 

 sides its extreme tenuity, it is readily distinguished from all its 

 congeners by the elevated lamina upon the columellar lip. It 

 inhabits the muddy bottom of a mill pond, in deep water, and 

 is found only when the water is drawn off. 



Genus Limnea. Lam. 



L. columella, Say. This, and the variety clialyhea, Gould, 

 is found in most of the fresh water collections in the State. I 

 have received the finest specimens from Brunswick. The 

 black variety of Gould is uniformly more elongated than the 

 usual type of L. columella, and appears to me to be much 

 more worthy of a place as a distinct species than many others 

 which are admitted without hesitation. 



L. humilis, Say. Several varieties of this species are found 

 in different parts of the State. I have observed an umbili- 

 cated variety in little puddles within the limits of the city, 

 that entirely dry up and disappear in the drought of summer. 

 How are the animals sustained during these seasons ? 



L. desidiosa, Say. Found in the counties of Cumberland 

 and Kennebeck. Dwarfish, — rare. 



L. decollata, Migh. Although I entertain the highest re- 

 spect for the opinion of ]\Ir. Haldeman, I cannot agree with 

 him in regarding this as a variety of L. catascopium, Say. I 

 do not think there is a striking resemblance between it and 

 the specimens he has introduced to illustrate his opinion, (Mo- 



