MARINE MOLLUSCA OF THE UNITED STATES. 169 
2. L. pustnua, Gould. 
Proc. Bost. Soc. Nat. Hist., viii. 282. 1862. 
Shell minute, reniform, yellowish, slightly concentrically striate ; 
umbones a little posterior, elevated; anterior dorsal margin exca- 
vated, extremity retusely rounded; posterior extremity broadly 
rounded, subtruncated; within radiatingly striated, the strice 
evanescent towards the umbones. 
Length 3, height 2.5 mill. 
Coast of North Carolina. (Coast Survey.) 
3. L. pEntTatTA, Wood. Fig. 427. 
Gen. Conch., 195, t. 46, f. ‘7. 1817. 
Lucina strigilla, Stimpson, Shells N. E., 17. 1851. 
Lucina Americana, C. B. Adams, Contrib. Conch., 248. 1852. 
Lucina divaricata, Lamarck (not Linn.), Anim. s.:Vert., v. 541. 1818.! 
Shell thin, orbicular, equilateral; beaks small, prominent, 
inclined forwards; basal margin regularly rounded and crenate. 
“Surface with well-marked concentric-lines, crossed by deep, oblique, 
narrow furrows, flexed at nearly right angles at the anterior third 
of the surface. White. 
Length 25, height 22 mill. 
Entire Coast. (Distribution universal.) 
4. L. TIGERINA, Linneeus. Fig. 428. 
Syst. Nat., edit. xii. 1133. 1767. 
Shell oblong-ovate, longer than high, flatly convex, radiately 
many grooved, very closely decussated throughout with concentric 
ridges ; white within and without. 
Southern Coast. (W. Ind.) 
5. L. EpENTULA, Linnzeus. Fig. 429. 
Mus. Ulric, 74. 
Lucina chrysostoma, Phil. Zeit., Malak., ii. 181. 1845. 
Shell orbicular, rather thin, ventricose, superficially excavated 
from the umbones on each side, concentrically finely and closely 
striated, teeth obsolete; semitransparent white, orange within. 
Southern Coast. (W. Ind.) 
' For full synqnymy and notes on this species, see TRyoN, Proc. Philad. 
Acad., 85. 1872. 
