152 AMERICAN MARINE CONCHOLOGY. 



somewhat pointed behind ; white or pink, covered with a dusky 

 epidermis. Teeth, two in each valve, slender and slightly diverg- 

 ing, the largest grooved. 

 Length 25, height 20 mill. 



Whole Coast, Arctic Seas, N. Europe. 



2. M. CALCAREA, Chemnitz. Fig. 368. 



(Tellina.) Conch. Cab., vi. 140, f. 136. 1782. 

 Tellina sabulosa, Spengler, Skrivt, Nat. iv., Pt. 2. 1798. 

 Tellina proximo,, Gray, Zool. Beechey's Voy., 154, t. 44, f. 4. 1839. 

 Tellina sordida, Couthouy, Bost. Journ. Nat. Hist., ii. 59, t. 3, f. 11. 



Shell thin and fragile, inequilateral, subtriangular, slightly 

 gaping. Epidermis thin and brittle ; beneath which the surface 

 is marked with numerous incremental lines. Beaks very small 

 and behind them the margin slopes away in nearly a straight 

 line. Teeth two in each valve, the largest bifid. White, covered 

 by a thin, brownish epidermis. 



Length 22, height 15 mill. 



Arctic Seas to New York. 



Wider and more triangular and depressed than the preceding 

 species. 



3. M. SUBROSEA, Conrad. Fig. 369. 



Am. Journ. Conch., vi. 71, t. 1, f. 3. 1871. 



Subtriangular, equilateral, convex ; substance very thin ; beaks 

 slightly prominent, direct ; posterior side cuneiform ; ventral 

 margin rounded, disk minutely striated concentrically, white or 

 rosaceous and glossy, with a thin, pale ochreous epidermis ; cardi- 

 nal tooth in the left valve compressed, with a minute linear sulcus. 



Raritan Bay, N. J. ; Delaware Bay.' 



Doubtful Species. 



4. M. TENUIS, Da Costa. Fig. 3TO. 



(Tellina.) Conrad, in Say's American Conchology, vii. t. 64, f. 3. 

 Shell oval-triangular, irregularly striate concentrically ; each 

 valve with two teeth and one of them with lateral teeth. 



Sullivan's Island, S. Oar. 



The above meagre description and figure represent a shell sent 

 to Mr. Say by Prof. Ravenel of Charleston, S. C., which Mr. Con- 

 rad has identified as M. tennis. I am not aware that it has since 

 been found on our coast. 



