MARINE M0LLUSCA OF THE UNITED STATES. 169 



2. L. pusilla, Gould. 



Proc. Bost. Soc. Nat. Hist., viii. 282. 1862. 



Shell minute, reniform, j T ellowish, 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 strire 

 evanescent towards the umbones. 



Length 3, height 2.5 mill. 



Coast of North Carolina. {Coast Survey.) 



3. L. dentata. 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. Couch., 243. 1852. 

 Lucina dicarieata, 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, Linnaeus. Fig. 428. 



• Syst. Nat., edit. xii. 1133. 1767. 

 Shell oblong-ovate, longer than high, flatly convex, radiately 

 man}- grooved, very close!}' decussated throughout with concentric 

 ridges ; white within and without. 



Southern Coast. (W. Ind.) 



5. L. edentula, Linnaeus. 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. ) 



1 For full synonymy and notes on this species, see Tryon, Proc. Philad. 

 Acad., 85. 1872. 



