LEDA. 161 



is obtusely pointed as tlic regular curve of the base meets the dorsal 

 line, though in many instances there is a slight flexure just below 

 the point. Interior yellowish-white, glossy, with greenish zones, 

 and minute radiating lines or strioe : cartilage cavity deep, triangular; 

 series of teeth about twelve on each side, but sometimes increased 

 to sixteen or eighteen, increasing in size and distance towards tlie 

 outer extremities. Length, one and one tenth of an inch ; heiglit, 

 seven tenths of an inch ; breadth, seven twentieths of an inch. 



Taken from the stomachs of fish caught in various parts of ]\Ias- 

 sachusetts Bay. Eastport to Cape Cod, Grand Maium ( Stimpson) ; 

 Gulf St. Lawrence (Mig-hcls) ; Halifax CiVU/is). 



The general aspect of this species is like that of Y. limatula. It 

 is distinguished by the position of the beaks, and the smaller num- 

 ber of teeth ; the whole shell, and the posterior portion especially, 

 is less elongated, and the epidermis is of a darker, more strictly 

 olive color, and far less glossy. It never attains to so great a 

 size. It has almost precisely the shape and size, but none of the 

 oblique stri^ of N. arctica, Broderip and Sowerby. A shell from 

 Spitzbergen sent me by Dr. Loven, and named liy him iV". hijpcrhorea^ 

 as to the exterior and the position of the beaks is like this ; but its 

 height is less, and there are eighteen teeth in the posterior range. 

 [Doubtless identical. 



Oeniis LEDA, ScnoiAcnER. 1817. 



Shell produced behind and rostrate, line of teeth interrupted by 

 the oblique, depressed deltoid pit for the ligament, most numerous 

 behind the pit ; pallial sinus very small. Mantle open, simple ; 

 foot large, clulvshaped, divided below and dilatable into a disk ; 

 siphons formed by a coherence of the mantle at three points. 



Leda tenuisulcata. 



Shell ovate-lanceolate, inequipartite, posteriorly much narrowed and rostrated ; 

 surface with numerous concentric ridges, covered with a light greenish-yellow 

 epidermis ; teeth twelve before and sixteen behind the beaks. 



Nucula tennisnkata, Couthouy, Bost. Journ. Nat. Hist. ii. 64, pi. 3, fig. 8 (18.38). — 

 Hanley, Biv. 377, pi. 20, fig. 17. — Philippi, in Meiike's Zcitsch. 75 (1845). 



Nucida miniila, Gould, Invert. 101. — De K.\.y, Nat. Hist. New York, 181. — Mighels, 

 Shells of Maine, 17, and Bost. Journ. iv. 323. 



Ledateniiisidcaia, Hanley, in Thes. Conch, iii. 112, pi. 228, fig. 87 (1860). — Stimpson, 

 Inv. Gr. Manan, 21 ; Shells of New England, 10 (1851). 

 11 



