28 [J UNE , 1841. 



upper surface, transverse diameter 2-5 of an inch, height 1-6 of 

 an inch. Brought from North Carolina by Mr. T. Nuttall. 



This shell differs from all the known American Helices, in the 

 character of the two minute, well defined teeth on the outer lip, 

 while it is without a trace of a tooth on the pillar lip. 

 Helix lasmodon. Testa subelevata, centiculata, crassiuscula, urn- 

 bilicata, substriata ; apertura compressa ; labro acuto, uno vel 

 duobus dentibus lamellosis ; base rotundato ; colore albo corneo. 

 Shell moderately elevated, lenticular; rather thick; epidermispale 

 whitish horn colour, smooth, shining ; whorls eight, very faintly 

 and obliquely striated ; suture indistinct ; aperture compressed, 

 within a broad calcerous deposit, and one or two lameller teeth 

 following the direction of the whorls ; lip acute ; umbilicus mod- 

 erately large, rounded and deep ; base regularly rounded into the 

 umbilicus. Transverse diameter 7-20, height 3-20 of an inch. 

 Brought from Alabama by Dr. W. Blanding. 



This shell resembles no other American species but H. suppressa 

 Say, and H. gularis Say, and from these it differs decidedly in the 

 well defined and deep umbilicus ; it differs from H. Epistilium, in the 

 smaller size, greater number of whorls, large umbilicus and lentic- 

 ular form. 



Mr. T. A. Conrad read a paper descriptive of twenty-six 

 new species of Fossil shells, discovered by him in the Medial 

 Tertiary deposits of Calvert Cliffs, Maryland, viz. : 



Venus. 



Venus latilirata. Trigonal, convex depressed, ribs concentric, 

 about 5 or 6 in number, flattened, reflected, irregular, one of 

 them generally very wide ; ribs irregularly sulcated on the pos- 

 terior slope ; inner margin finely crenulated. Smaller than V. 

 alveata, and with broader, less prominent ribs, which do not 

 diminish in size on the posterior margin. 



Cytherea. 

 Cytherea subnasuta. Trigonal, thin, ventricose ; anterior side nar- 



