MARINE MOLLUSCA OP 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 SILIQUAKIA, Schum. 

 Essai, Nov. Gen., 129. 1817. 



1. S. GIBBA, Spengler. Fig. 332. 



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

 Solecurtus caribcBus (Lam.) 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., southwards. 



2. S. DIVISA, Spengler. Fig. 333. 



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

 Solen fragilis, Pultney, Dorset Cat., 28, t. 4, f. 5. 1799. 

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

 Solen ttdens, Chemn. Conch. Cah., xi. 203, 1. 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 SILIQTJA, Muhlfeldt. 



Entwurf. 44. 1811. 

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



1. S. SQUAMA, Blainville. Fig. 335. 



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

 Machcera 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, northwards. 



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 



