1854.] 165 



dorsal carina, aperture sub-trigonal, surface marked with delicate, arched striae 

 of growth. 



Width, 2s lines ; height h of a line. 



Occurs very abundantly. 



Lymnea diaphana. (Nov. sp.) 



Shell small, oblong, ovate- conic ; whorls fine, convex, crossed by delicate lines 

 of growth, spire short, acute at apex ; aperture oval, slightly dilated, rather 

 larger than half the length of the shell; columella rather delicate and sinuate, 

 umbilicus minute. 



Length, 2j lines ; width, 1J- lines ; length of aperture, \h lines. 



Very common. 



Lymnea Nebrascensis. (Nov. sp.) 



Shell ovate, sub-conic, volutions five, convex, crossed by minute, elevated 

 lines of growth ; body whorl ventricose, more than twice the length of spire ; 

 spire short, apex pointed, suture not deeply impressed ; lip produced in front. 



Length, 5 lines ; length of body whorl, 4 lines ; width about 2^ lines. 



All the specimens in our possession are very much compressed, and other- 

 wise mutilated, so that the form and character of the aperture cannot be deter- 

 mined. It is very similar to the preceding species, from which it is distinguished 

 by its greater size and its numerous crowded striae. 



PHYSA SE.CALINA. (Nov. Sp.) 



Shell small, thin, oblong-oval ; volutions four, evenly convex, smooth or with 

 very fine lines of growth ; aperture ovate, narrow, more than equal to the entire 

 length of the shell ; spire short, slightly rounded at summit, suture distinct but 

 slightly impressed. 



Length, 2 lines ; width, \\ lines. 



Only two specimens of this little shell have come under our observation, and 

 these rather imperfect. 



Cypris Leidyi. (Nov. sp.) 



Carapace minute, reniform, vertical section sub-cordate, width of extremities 

 nearly equal ; central and anterior portions of surface very convex, the convexi- 

 ty diminishing towards the posterior end; ventral margin straight or very slightly 

 concave, about one third shorter than the entire length of the valves; dorsal and 

 lateral margins convex, encircled by a well defined, narrow groove, which ter- 

 minates at the ventral margin ; surface covered with exceedingly minute gra- 

 nulae. 



Length, I of a line ; width, \ ; thickness, 2-5th. 



A close examination of the slabs of fresh water limestone from the vicinity of 

 Peno Creek, has resulted in the discovery of this pretty little crustacean. The 

 substance of the fossil is nearly transparent chalcedony, and the valves in both 

 specimens remain attached in their normal position. 



Named in honor of Prof. Joseph Leidy, whose valuable researches have con- 

 tributed so largely to our knowledge of the fossil fauna of Nebraska. 



The Committee on Dr. Hallowell's paper, entitled, "Contributions 

 to South American Herpetology/' reported in favor of publication in 

 the Journal. 



ELECTION. 



Mr. Joseph Harrison and Garrick Mallery, Esq., of Philadelphia, 

 were elected Members, ; and Dr. Win. E. Dearing, of Augusta, Georgia, 

 was elected a Correspondent. 



