182 AMERICAN MARINE CONCHOLOGY. 



covered with numerous concentric ridges ; epidermis greenish- 

 yellow to brownish ; teeth twelve anterior and sixteen posterior 

 to the heaks. 



Length 25, height 11 mill. 



New England, northwards. 



2. L. Jacksonii, Gould. Figs. 490, 491. 



(JVucula.) Invert. Mass., edit. i. 102, f. 5. 1841. 

 Leda buccaia, Steenstrup, MoUer, Moll. Grceul. 17. 1842. 



Shell ovate, swollen, a little beaked and narrowed behind, sur- 

 face concentrically ridged ; teeth 15 in front and 20 behind the 

 beaks. 



Length 25, height 14 mill. 



Maine, northtcards. 



This shell is higher in proportion to its length, and not so nar- 

 rowly I'ostrated as L. tenuisulcata ; it differs also in the number 

 and arrangement of the teeth. 



3. L. minuta, Fabricius. Figs. 492, 493. 



(Area.) Fauna Graml. 414. 1780. 

 Shell oblong, inflated, somewhat pear-shaped, posterior side not 

 much produced; brownish; 12 teeth before and about 14 behind 

 the beaks. 



Length 12.5, height 7.5 mill. 



Halifax, N. S. 



More nearly equilateral than the other species. 



4. L. CAUDATA, Donov. Figs. 494, 495. 



(Area.) Brit. Shells, t. 78. 



Shell long, depressed, slender ; epidermis 3'ellowish, ridged. 



Length 15, height 6.25 mill. 



Halifax, nortlncards. 



Smaller than ^e?H«'swZca/n, and more recurved posteriorly; the 



beaks also are more acute and less tumid. 



5. L. ACUTA, Conrad. Fig. 496. 



{Nucitla.) Am. Mar. Concb., t. 6, f. 3. 



Shell ovate, elongated, convex, with numerous, regular, concen- 

 tric striifi ; posterior side slighth^ recurved, and very acute at the 

 extremity ; epidermis dark green. 



Length 6, height 4 mill. » 



North Carolina. 



This- species was first described by Mr. Conrad as a doubtful 

 fossil; it lives abundantl}- near Fort Macon, N. C. 



