[16 ] 



SUCCINID^. 



SUCCINEA, Draparnaud. 



Shell obliquely ovate, imperforate, very thin, unicolorefl, 

 corneous, transparent or translucent ; spire very small, body 

 whorl large, inflated ; aperture large, oval or ovate^ peristome 

 simple, acute. 



Animal large, with short and thick tentacles ; foot broad. 

 Buccal plate with a posterior quadrangular projection for the 

 attachment of its muscles'; cutting edge with one or more 

 projections or folds, not striate. 



Semi aquatic, inhabiting low, damp ground liable to over- 

 flow, on the margins of bodies of water, and frequently adher- 

 ing to the leaves of aquatic plants. Generally, large numbers 

 of a species are found together^ — at least of those northern 

 species with the habits of which we are most familiarly ac- 

 quainted. One species, however, S. avara, is very frequently 

 found solitary or in pairs only, and appears to be somewhat 

 different in its habit, as I have frequently taken it in shady 

 places on high ground, far removed from bodies of water. 



There appears to be two distinct groups or sub-genera of 

 S'tccinese inhabiting North America; the first, characterized 

 by well-rounded whorls, is recognized by malacologists as 

 typical; the second, with the shell ovate, and the whorls flat- 

 tened above and efi'use below, has received the name of Bra- 

 chyspira, Pfr. 



Examined with a view to geographical distribution, we find 

 the two groups of Succinem to have their representatives in 

 every part of the Union, and yet, so far as we may presume to 

 generalize from the very insufficient data wliich has been col- 

 lected and published, the species appear to be much less dif- 

 fused throughout the country than those of the Helices. The 

 following table will give an idea of their territorial range: — 



1. Inhabiting the Northern States westward to the Rocky 

 Mountains, extending into British America, southwards 

 to Virginia and Tennessee. 

 7, S. obUqua, 10, S. vermeta, 11, S. avara, 21 S. ovalis, 32, 

 S. aurea. 

 a. Confined to New England States. 

 1, iS. TdUnairm.a. 



I). Confined to northern frontier of the United States and north- 

 wards. 

 12, S. Groenlandica, 14, S. Verilli, 22, S. Decampii, 23, 

 S. Sigginsi. 

 c. Ohio. 

 21, iS. retusa. 



