182 AMERICAN MARINE CONCHOLOGY. 



covered with numerous concentric ridges ; epidermis greenish- 

 yellow to brownish ; teeth twelve anterior and sixteen posterior 

 to the beaks. 



Length 25, height 11 mill. 



New England, northwards. 



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



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

 Leda buccata, Steenstrup, Moller, Moll. Groenl. 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, northwards. 



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

 rowly rostrated as L. tenuisulcata ; it differs also in the number 

 and arrangement of the teeth. 



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



(Area.) Fauna Groenl. 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. 8. 



More nearly equilateral than the other species. 



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



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



Shell long, depressed, slender; epidermis yellowish, ridged. 



Length 15, height 6.25 mill. 



Halifax, northwards. 



Smaller than tenuisulcata, and more recurved posteriorly; the 



beaks also are more acute and less tumid. 



5. L. acuta, Conrad. Fig. 496. 



(Nucula.) Am. Mar. Conch., t. 6, f. 3. 



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

 tric strire; posterior side slightly 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 abundantly near Fort Macon, N. C. 



