Li;i)A. IGl 



is ol)tusely pointed as the regular curve of the l)ase meets the dorsal 

 line, though in many instances there is a slight flexure just l)elow 

 the i)oint. Interior yellowish-white, glossy, with greenish zones, 

 and minute radiating lines or stria) ; cartilage cavity deep, triangular; 

 scries of teeth ahout twelve on each side, but sometimes increased 

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

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

 seven tenths of an inch ; l)readth, seven twentieths of an inch. 



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

 sachusetts Bay. Eastport to Cape Cod, Grand Manan (^Stimpson} ; 

 Gulf St. Lawrence (Mig'hels) ; Halifax (Wil/us). 



The general aspect of this species is like that of Y. limatnla. 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 striae of N. arctica, Broderip and Sowerby. A shell from 

 Spitzbergen sent me by Dr. Loven, and named by him iY. ht/perborea, 

 as to the exterior and the })Osition of the beaks is like this ; but its 

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

 [Doubtless identical. 



Ociitis LED A, v'^cnr.MACHER. 1817. 



Shell produced behind and rostrate, line of teeth interrupted by 

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

 behind the pit ; |:)allial sinus very small. Mantle open, simple ; 

 foot large, clul)-shaped, divided below and dilatable into a disk ; 

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



Leda tenuisulcata. 



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

 surface with numerous concentric ridges, covered Avith a light greenish-yelloAV 

 epidermis ; teeth twelve before and sixteen behind the beaks. 



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

 Hanley, Biv. .377, pi. 20, fig. 17. — PHiLipn, in Menke's Zeitscli. 75 (1845). 



Nucula minuta, Gould, Invert. 101. — De Iv.\.y, Nat. Hist. New York, 181. — Mighels, 

 Shells of Maine, 17, and Best. Journ. iv. .32-3. 



Lcda tenuisulcata, Hanley, in Thes. Couch, iii. 112, pi. 228, fig. 87 (1860). — Sti.aipson, 

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

 11 



