MARINE MOLLUSCA OF THE UNITED STATES. 143 



parallel with the dorsal and basal margins. Greenish-olive, the 



central space faded purple. 



Length 6, height 1 inch. 



Whole Coast. 



Distinguished from E. ensis of Europe by its greater propor- 

 tionate width of valves. It is altogether a more robust and larger 

 species. 



Found at low-water mark, and considered excellent food. 



Genus SILIQUARIA, Schum. 

 Essai, Nov. Gen., 129. 1817. 



1. S. gibba, Spengler. Fig. 332. 



(Solen.) Skrivt. Nat. Selsk., iii. 104. 1794. 



Solecurtuscaribanis (Lain.) Conrad, Mar. Conch., t. 4, f. 3. 



Shell thick and solid, beaks obtuse and little elevated. Surface 



with a thick, straw-colored, concentrically wrinkled epidermis. 



Length 4, height 1.5 inches. 



Cape Cod, Mass., soutliwards. 



2. S. divisa, Spengler. Fig. 333. 



(Solen.) Skrivt. Nat. Selsk., iii. 96. 1794. 

 Solenfragilis, Pultney, Dorset Cat., 28, t. 4, f. 5. 1799. 

 Solen centralis, Say, Journ. Philad. Acad., ii. 316. 1822. 

 Solen Mdens, Chemn. Conch. Cab., xi. 203, t. 198, f. 1939. 1795. 



Shell small and delicate, transversely oblong-ovate, compressed, 



arcuated, equilateral. Epidermis yellowish, with a purple band 



from the beaks to the basal margin. 



Length 1.5, height .5. 



Southwards from Cape Cod, Mass. 



Genus SILIQUA, MUhlfeldt. 

 Entwurf. 44. 1811. 

 Machcera, Gould, Invert. Mass., p. 32. 1841. 



1. S. squama, Blainville. Fig. 335. 



{Solecurtus.) Diet. Sci. Nat., xlix. 419. 

 Machmra nitida, Gould, Invert. Mass., 33. 1841. 



Shell thick, oblong-ovate, beaks small ; epidermis very shining, 

 dark yellowish or greenish-yellow, wrinkled. 



Length 3, height 1.25 inches. 



Northern Coast, northward*. 



2. S. costata, Say. Figs. 334, also 299 and 300. 



{Solen.) Journ. Philad. Acad., ii. 315. 1822. 



Shell thin and fragile, oval-oblong, much compressed, beaks 



