98 JOURNAL OF THE NEW JERSEY 



and the lines of growth very fine. Color very pale yellowishy 

 covered by a thin, darker epidermis; yonng specimens are 

 covered more or less with zigzag blotches of fawn color ; inside 

 margin white, centre bright yellow with a dark, purplish blotch 

 along the posterior side. L. 23 ; H. 23 ; W. 20 ; U. nearly cen- 

 tral. — Whole coast. Most abundant on shallow flats, and at 

 creek mouths ; rare north of Cape Cod. 



Family 15. VENILIID/E, 



Shell solid, rounded, closed ; epidermis thick and dark ; liga- 

 ment large external ; cardinal teeth three in each valve ; pallial 

 line almost entire; siphons very short; foot thick. 

 1. Cyprina, Lam. 



Shell oval, large, strong ; no lunule ; no pallial sinus. 



1. Cyprina Islandica^ L. Shell closed, obliquely ovate or heart- 

 shaped, tumid, thick and solid ; umbones approximate, usually 

 eroded ; epidermis coarse , strong and rough, with crowded and 

 loose wrinkles; inner margin without crenulations. Epidermis 

 dark, shining brown to almost black ; inside chalky white. L. 

 80 ; H, 75 : W. 45 ; U. J. 



Animal with a plain mantle open in front and below. — New 

 England, Thrown upon the beach, after storms. 

 Family 16. VENERID/E. 



Shell regular, closed, sub-orbicular to oblong; ligament ex- 

 ternal ; hinge with usually three diverging teeth in each valve : 

 muscular impressions oval, polished ; pallial line with a sinus. 



Animal free, locomotive, rarely byssiferous or burrowing ; 

 mantle with a rather large opening for the foot; siphons un- 

 equal, united more or less ; foot narrow, compressed. 



* No lunule; size minute, under 6 long .2. Gemma. 



* With well marked lunule ; size large, over 25 long. (A.) 



A. Length about equal to height 4. Dorsinia. 



A. Length plainly greater than height, (B.) 



B. Inner edge not crenulated ; 4 cardinal teeth in one valve..<9. Cytherea. 

 B. Inner edge crenulated ; 3 cardinal teeth in each valve. (O.) 



C. No distinct, radiating lines ; pallial sinus not extending to the 



middle 1. Venus. 



1. Venus, L. 



Shell thick, ovate ; inner edge crenulated ; cardinal teeth 3 in 

 each valve; pallial sinus small, angular ; ligament prominent; 



