CONCHACEA. MOLLUSCA. CYI'RINA. 83 



State Coll., No. 201. Soc. Cab., No. 1815. 



Pectunculus maximus, Lister ; Conch., t. 272, f. 108. 



Pectunculus crassus, Da Costa ; Brit. Conch., 183, pi. 14, f. 5. 



Venus Islandica, Lin.; Syst. JVat , li:il. Gmei.in ; Stjst., '327] . Montagu; 



Test. Brit., 114. Maton and Rackett ; Lin. Trans., viii. 83. Wood ; in 



Li7i. Trans., vi. t. 17, f. 1, $i. Dillvvyn ; Catal., 17G. Chemn.; Conch., vi. 



340, pi. 32. f. 341. Donovan; Brif. Shells, iii. pi. 77. Muller; Zool. Dan., 



i. 29, pi. 28, f. 1 to 5. Turton ; Conch. Diet., 238. 

 Venus mercenaria, Pennant ; Brit. Zool., iv. pi. .53, f. 47. 

 Venus bucardium, Born; Mus., pi. 4, f. 11. 

 Cyprina Islandica, Lam.; An. sans Vert., vi. 290. Desuaves; Encyc. J\l6lh., 



Vers, i. 46, pi. 272, f. 6. Bi.ainv. ; MalacoL, p], 70 his, f. 5. Turton ; Brit. 



Biv., 135. Fleming ; Brit. Anim., 444. 

 Cyprina vulgaris, Sowerey ; Genera. 



Shell large, thick and heavy, ovate orbicular, tumid ; beaks 

 elevated, pointed, turned forwards and inwards so as to come 

 nearly in contact ; anterior side shorter, narrower, rounded and 

 compressed ; posterior side full and broad at the back, slightly 

 angular at the extremity ; a very superficial ridge passes from the 

 beaks to the lowest posterior point ; the space which they in- 

 clude is very coarsely wrinkled ; there is a shallow oval pit before 

 the beaks, but no distinctly marked lunule ; the ligament is strong 

 and protuberant ; epidermis of a dark, shining, burnt-brown color, 

 sometimes almost black, coarse and strong, rough with crowded 

 and loose wrinkles ; hinge margin broad and strong ; cardinal 

 teeth diverging, three in each valve, or rather one large double 

 tooth and a small one in the right valve ; lateral tooth along the 

 posterior margin, slightly developed, blunt ; inside chalky-white, 

 muscular and palleal impressions superficial, the latter having no 

 sinus ; margin at base sharp and simple. Length 3| inches, height 

 3 inches, breadtli 1| inch. 



This shell is an inhabitant of all the northern Atlantic seas, 

 especially near where some river empties into the ocean. It is 

 sometimes thrown upon our beaches in great numbers after storms, 

 being driven up from deep water. The young are found abun- 

 dantly in the stomachs of fishes taken in Massachusetts Bay. It 

 appears not to be common, if it is found at all, to the southward 

 of Massachusetts. 



It is one of our largest shells, and resembles no other shell of our 

 coast except the Venus mercenaria, with which it was confounded by 



