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. JAcksonil, Gould. Figs. 490, 491. 
(Nucula.) Invert. Mass., edit. i. 102, f. 5. 1841. 
Leda buccata, Steenstrup, Moller, Moll. Greenl. 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. 
8. L. minuTA, Fabricius. Figs. 492, 493. 
(Area.) Fauna Greenl. 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. cAupATA, Donoy. Figs. 494, 495. 
(Area.) Brit. Shells, t. 78. 
Shell long, depressed, slender; epidermis yellowish, ridged. 
Leneth 15, height 6.25 mill. 
Halifax, northwards. 
Smaller than tenwisulcata, 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 strive; 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. 
