148 AMERICAN MARINE CONCHOLOGY. 
valve ; lateral teeth none. Muscular impressions strong ; pallial sinus 
large and broad. ERVILIA. 
Genus Tellina, Linnzus. 
Syst. Nat., edit. x. 674. 1758. 
1. T. ALTERNATA, Say. Fig. 345. 
Journ. Acad. Nat. Sci. Philad., ii. 275. 1822. 
Shell compressed, oblong, narrow and angulated behind ; nume- 
rous impressed concentric lines, alternately obsolete, on the pos- 
terior margin. Within, a callous line passes from behind the 
hinge to the inner margin of the posterior cicatrix. Posterior 
hinge tooth emarginate ; anterior lamellar tooth near the cardinal, 
so as to appear like a primary tooth; that of the right valve 
wanting; posterior lamellar tooth at the extremity.of the liga- 
ment. Posterior hinge-slope declining in a concave line to an 
obliquely truncated tip. White, tinged with yellow within. 
Length 55, height 31 mill. 
North Carolina to West Indies. 
9. T. pomiTaA, Say. Figs. 346, 347, 348. 
Journ. Philad. Acad., ii. 276. 1822. 
Shell transversely subtriangular, with minute concentric wrin- 
kles; anterior margin rather shortest; hinge slope declining in a 
very slightly arcuated line to a subacute termination; basal 
margin nearly straight from before the middle to the posterior 
end ; a lateral tooth behind the primary-one. White immaculate. 
Length 15, height 10 mill. 
North Carolina, southwards. 
3. T. TENERA, Say. Fig. 349. 
Journ. Philad. Acad., ii. 803. 1822. 
Shell very thin and fragile, pellucid, compressed, transversely 
oblong, suboval; covered by delicate concentric lines of growth. 
Beaks placed slightly posteriorly ; marginal folds distinct ; basal 
margin slightly arcuated. Posterior cardinal tooth in the left 
valve largest; the other often indistinct; the chief tooth in each 
valve grooved; lateral tooth on the longest side distinct; the 
others very indistinct. White, iridescent, occasionally rosaceous. 
Length 14, height 9 mill. 
Nova Scotia to S. Carolina. 
Found abundantly on sandy beaches, and probably lives not 
far from low-water mark. 
