MARINE MOLLUSCA OF THE UNITED STATES. 151 
opalescent, with a purple or bluish iridescence often in the form 
of rays. 
Length 17, height 10 mill. 
New York. 
Genus STRIGILLA, Turton. 
Brit. Bivalves, 117. 1822. 
This genus is readily recognized by its obliquely-sculptured 
valves and its orbicular shape. 
1. S. caARNARIA, Linneus. Figs. 362, 363. 
(Tellina.) Syst. Nat., edit. xii. 1119. 1767. 
Suborbicular, convex, strong, glossy, pink or rose color; inside 
rosy ; lateral teeth distinct and nearly equidistant. 
: Southern Ooast to W. Indies. 
2. S. FLEXuOoSA, Say. Figs. 364, 365. 
(Tellina.) Journ. Philad. Acad., ii. 308. 1822. 
Strigilla mirabilis, Phil; Wiegm. Archiy., 260. 1841. 
Shell suborbicular, white, smaller and more convex than S. 
carnaria, the flexuous lines more numerously angled. 
Length 12, height 11 mill. 
North Carolina to W. Indies. 
Doubtful Species. 
3. S. MERA, Say. Fig. 366. 
(Tellina.) Am. Conch., vii. t. 64, f 2. \ 
Shell ovate-orbicular, concentrically striated, hinge bidentate, 
with a lateral tooth in one valve. 
South Carolina. 
The above description and figure refer to a species which has 
not been identified; its analogies of form would seem to indicate 
its position in this genus. Mr. Say remarks that “in a particular 
light it has a slight appearance of longitudinal lines.” It is 
quite possible that it is a worn specimen of Strigilla in which the 
zigzag oblique lines are obsolete. 
Genus MACOMA, Leach. 
Journ. de Phys., lxxxviii. 465. 1819. 
1. M. BAuTuIoA, Linneus. Fig. 367. 
(Tellina.) Syst. Nat., edit. xii. 1120. 1767. 
Psammobia fusca, Say, Journ. Philad. Acad., v. 220. 1827. 
Shell thin and fragile, ovate orbicular, beaks small, almost 
central. Surface with concentric wrinkles; rounded before and 
