Fossil and Recent Shells. 345 



dermis; anterior and posterior sides each with an obscure fold ; beaks 

 centra], not elevated ; hinge edentulous; anterior muscular impres- 

 sion not greatly elongated. Length, one inch. 



This shell resembles the fossil L. anodonta, of Say, but is very 

 distinct. It was found near Pensacola by Dr. Hutchins, who sent 

 it to Dr. S. G. Morton. 



CYTHEREA. 



C. Sayana. Shell subovate, convex, with coarse concentric lines, 

 and destitute of polish ; lunule large, cordate, marked by a simple im- 

 pressed line; hinge, with the teeth compressed. Length, one inch 

 and one fourth. 



Syn. Cytherea convexa. Say. Jour. Acad. JVat. Sciences, vol. 

 iv, p. 149. 



Found on the coasts of Rhode Island and New Jersey; it is pale 

 yellowish or white and appears not to differ specifically from the C. 

 convexa, of Say, but I have changed the name because M. Brong- 

 niart had previously applied it to a very dissimilar species. 



melampus. 



Jkf. horealis. Shell ovate acute, elongated ; pale horn color with 

 darker longitudinal bands; whorls six or seven, with a revolving im- 

 pressed line below the suture; spire elevated, conical; columella 

 with three distant and distinct plaits, the middle one most prominent; 

 aperture obovate-acute. Length, one fourth of an inch. 



This small species of Melampus has been found sparingly on the 

 coast of Rhode Island, by Lieut. Brown of Newport. It is similar 

 in form to a Bulimus and is very unlike the common species with 

 which it associates. 



Ungulina transversa. Lam. As the history of this rare shell is 

 rather obscure, it may be worthy of remark, that I discovered two 

 specimens in a piece of limestone, inhabiting cavities which appeared 

 to have been formed by themselves. The limestone was perforated 

 in every direction by shells of the genera Jlrca, Crenatula, Vene.ru- 

 pis, Petricola, 8/-c., all the species being such as are common in the 

 West Indies, from whence no doubt, the stone which contained them 

 had been brought. From the circumstance of its occurring in this 

 situation and from the peculiar form of the shells, I have no doubt 

 that the genus Ungulina may be properly classed among the litho- 

 phagous Testacea. 



Lima glacialis. Lam. It is a singular fact in the history of this 

 shell that although it swims with great ease and rapidity, it is often 



Vol. XXIIL— No. 2. 44 



