OF coNCHOLoar.. 297 



DESCRIPTION OP A NEW SPECIES OF 

 MERCENARIA. 



BY GEORGE W. TRYON", JR. 



Mercenaria fulgurans, Trjon. — t. 26, f. 1, 2, 3. 



Description. — Shell sliort-ovate, somewhat heart-sliaped; cov- 

 ered with concentric, raised, sharp ribs, equidistant, extending 

 over the whole surface except the ligamental area and lunule ; 

 interstices concentrically striate; ligamental area long and 

 narrow, and, with the lunule, closely striate. Valves convex, 

 with the umbones elevated, and beaks recurved, sharp, and 

 approaching closely together. Color light cream, with very 

 narrow, light chocolate-colored, zig-zag markings ; lunule and 

 area chocolate. The same color tinges the crenulated margin, 

 while the shell is otherwise white within. 



Dimensions. — Length 40 millimetres, width 45 mill., diame- 

 ter 15 mill. 



SaUtat. — Tampa Bay, Florida. T. A. Conrad. 



My Cabinet. 



Observations. — This species resembles V. cingulata, Lam., 

 more than any other, in its markings, but is very distinct in 

 form, and in the narrow, raised ridges. In V. cingulata the 

 ridges are at first sharp and crenulated, but they subsequently 

 become thicker and more obtuse. 



