ARCACEA. MOLLUSCA. NUCULA. 101 



In its shape, and the perfect polish of its surface, this shell resem- 

 bles the seed of the Sapotilla (Achras sapota), a tropical fruit ; and I 

 have substituted that name instead of N. lavigata, under which I gave 

 the specific characters of the shell in the " American Journal of Sci- 

 ence," as I find that name preoccupied. 



NUCULA MINUTA. 



Shell ovate-lanceolate , inequilateral, posteriorly much narrowed 

 and rostrated ; surface with numerous concentric ridges, covered 

 with a light greenish-yellow epidermis ; teeth twelve before and six- 

 teen behind the beaks. 



State Coll., No. 180. Soc. Cab., No. 2339. 



Area minula, GMELIN ; Syst., 3309, 14. MONTAGU; Test. Brit., 140. CHEMN. ; 



Conch., x. 170, f. 1657, 1658. 

 Area caudata, DONOVAN ; Brit. Shells, pi. 78. 



Nucula minuta, TURTON j Brit. Bio., 178. FLEMING ; Brit. Jnim., 402. 

 Nucula rostrata, SOWERBY ; Genera, No. 17, f. 5. 

 Nucula tenuisulcata, COUTHOUY ; Bost. Journ. Nat. Hist , ii. 64, pi. 3, f. 8. 



Shell ovate-lanceolate, thin, the posterior side double the 

 length of the anterior, narrowed to a point, the tip being a little 

 upturned, truncated and gaping, the upper margin straight and 

 sharp ; anterior side regularly rounded ; surface wrought into 

 numerous and crowded concentric folds, excepting a compressed, 

 lanceolate area behind the beaks reaching nearly to the tips, which 

 is smooth and shining ; a delicate, sub-marginal angle runs from 

 the beaks to the lower angle of the truncated tip, at which the 

 concentric folds or ribs are bent at nearly a right angle, so as to 

 be parallel to the margin ; epidermis light greenish-yellow, or sap- 

 green color, within pearly white ; an elevated ridge runs from 

 within the cavity of the beaks to the lower angle of the truncated 

 tip, corresponding to the exterior angle ; teeth twelve to fourteen 

 before the beaks, and sixteen to eighteen behind them. Length 

 1 inch, height ' T inch, breadth T 3 7 inch. 



Found, not very rarely, in the stomachs of fishes taken off Na- 

 hant. 



This shell is readily distinguished from our other species by the 

 folds and grooves of its surface. It is much more pointed than the 



