OP CONCHOLOGY. 233 



10. Succinea vermeta, Say. 



Plate 2, figure 10. 



Ovate-lengthened, very thin, fragile, translucent, wrinkled ; 

 spire elevated, acute, suture profoundly impressed; volutions 3, 

 very much rounded, oblique ; aperture ovate, rounded above. 

 Yellowish. | 



Length 10, diam. 7 mill. 



Northern States. 



The great convexity of the whorls and very deep suture are 

 the distinguishing characters of this species. A large variety 

 of S. avara not possessing these characters has erroneously 

 passed among Conchologists as S. vermeta. 



11. Succinea avara, Say. 



Plate 2, figures 11 and 12. 



Ovate, thin, fragile, minutely hairy or shining, spire elevated, 

 acute, suture well impressed ; aperture broadly oval, a little 

 more than half the total length. Yellowish or greyish, frequent- 

 ly encrusted xcith dirt. 



Length 6, diam. 3| mill. 



Northern, Middle and Western States to Nebraska. 



The smallest of the northern species, readily distinguished 

 from No. 10 by its less scalariform volutions. In Greenland 

 it is replaced by the following species ; in the Pacific States by 

 S. Oregonensis ; in the far South by S. Haleana — all species of 

 about equal size. A western variety sometimes attains nearly 

 double the dimensions quoted above. 



This species frequently inhabits at a considerable distance 

 from water or low grounds. 



Mr. Isaac Lea has described a species from Ohio under the 

 name of S. Wardiana, which Mr. Binney believes to be iden- 

 tical with S. avara, in which opinion I coincide. As Mr. Lea 

 has recently reasserted the specific weight of his species,* I 

 have had a drawing made from the type (fig. 12) of S. Ward- 

 iana, to afford opportunity of making comparisons, as it had 

 not been previously figured. 



* Proceedings Acad. Nat. Sciences, 1865. 



