FAMILY SOLENID.E SOLECURTUS. 243 



(EXTRA-LIMITAL.) 



S. viridis. (Say, Ac. Sc. Vol. 2, p. 316. Conrad, Mar. Conch, pi. 5, fig. 2. Plate 33, fig. 312 

 of this book.) Shell transversely oblong-, compressed. Hinge-margin nearly straight : basal 

 margin rounded ; posterior end obliquely truncated, a little reflected and rounded near the base ; 

 anterior end rounded. Surface smooth, with very slight concentric lines, marking the various 

 stages of growth : hinge terminal. A single tooth in each valve, having a flattened vertical surface ■ 

 which turns upon that of the opposite tooth. Color : epidermis pale green, becoming olivaceous 

 with age. Vertical axis, 0-4; transverse, 2*0. Southern coast. 



Genus Lepton, Turton. Shell flat, nearly orbicular, equivalve, inequilateral, a little open at the 



sides. Hinge of one valve with a single tooth, and a transverse linear lateral one, each side ; 



the other valve with a cavity in the centre, and a transverse deeply cloven lateral tooth each 



side, the segments of which divaricate from the beak : ligament internal. 



L. fabagella. (Conrad, Mar. Conch, p. 51, pi. 11, fig. 3. Plate 32, fig. 307, a. b. of this book.) 



Shell very small, suboval, convex, with minute crowded concentric lines ; beaks central, rather 



prominent. Epidermis thin and wrinkled : teeth similar in each valve ; the posterior tooth longest, 



and angulated under the beak. Color : epidermis yellowish. Vertical axis, • 3 ; transverse, • 4. 



Rhode-Island. 



GENUS SOLECURTUS. Blainville. 



Animal too large for its shell. Lobes of the mantle thick in front, united and elongated in 

 its posterior half into two large unequal siphons, which are united very near the summit. 

 Foot tongue-shaped, large, very thick. Labial appendices very long and narrow. Branchiae 

 narrow, very long, extending through the whole length of the branchial siphon. Shell 

 transverse, elongated, equivalve ; the beaks small, subcentral. Margins nearly parallel ; 

 ends abruptly rounded. Hinge with two or three cardinal teeth in each valve : ligament 

 prominent, seated on thick callosities. Palleal impression with a very deep sinus. 



SOLECURTUS CARIBOUS. 

 PLATE XXXII. FIG. 302. 



(STATE COLLECTION.) 



Solen carib<cus. Lam. An. sans vert. Vol. 2, p. 522. Ed. Brux. 



Solecurtus caribants. Conrad, Ana. Marine Conchology, p. 22, pi. 4, fig. 2. 



S. (Cullellus.) id. Godld, Invertebrata of Mass. p. 30. 



Description. Shell thick and solid, transversely elongated, resembling in shape some species 

 of Unio, rounded at both ends ; the upper and basal margins nearly parallel, the latter 

 compressed and slightly arcuated. Beaks obtuse and little elevated, and placed towards the 



31* 



