NUCULIDiE. 141 



rotundato-acuminata, radio nullo impressa, subhevigata, cute niti- 

 dissima valida flavescente-olivacea induta. Margo dorsalis anticus 

 vix declivis; posticus declivis, subrectus; ventralis antice arcuatus 

 et multum acclivis. Nates acutissimse, baud autem eminentes. 

 Area; dorsales baud definitse : lunula planulata : area; labia carinato- 

 protrusa. — Somewhat elliptical, very inequilateral, much com- 

 pressed, covered by polished yellowish-olive strong epidermis, 

 devoid of umbonal ridge or anterior ray, smooth, except for the 

 wrinkles of increase. Anterior side much produced, its extremity 

 somewhat tapering, unsymmetrically rounded. Posterior side 

 short, quickly tapering to a rounded peak which lies rather above 

 than below the middle. Front dorsal slope almost horizontal, at 

 first straightish, eventually convex. Hinder dorsal slope moderate, 

 straightish. Ventral margin obliquely arching up in front, merely 

 broadly convex in the middle, subarcuatedly rising behind. Beaks 

 peculiarly sharp, yet not prominent. Dorsal areas undefined ; the 

 front one flattened, sometimes impressed ; lips of the escutcheon 

 carinately pouting. Teeth rather few (about nine and twelve at 

 most) on either side of the cartilage-pit, which latter is depressed, 

 and has its base rounded. — There is some faint trace of an in- 

 dented ray near the hinder extremity. 



63. L. sapotilla, Gould, f. 16. — T. sequilateralis, subventri- 

 cosa, Isevis, subovalis, postice obtuse acuminata et paullulum 

 subrostrata, cute polita luteo-subvirescente induta. Margo dorsalis 

 anticus arcuatus, vix declivis ; posticus rectior, leviter declivis ; 

 ventralis antice subito et obhque acclivis, postice subsinuatus. 

 Area; dorsales baud definitse. Nates baud eminentes. — Suboval, 

 subventricose at the umboes, only slightly gaping at the extremi- 

 ties, pure white under a polished fugacious oil-yellow cuticle, 

 smooth, or at most with wrinkles of increase. Sides equal or 

 very nearly so ; the anterior, if either, the shorter, unsymmetrically 

 rounded ; the posterior bluntly peaked, and, from the slight ven- 

 tral flexure, a little subrostrated, the tip rounded. Front dorsal 

 edge arched, scarcely sloping : hinder one straighter, a little 

 sloping. Ventral margin a little convex in the middle, abruptly 

 and obliquely ascending in front, couvexly rising behind, forming 

 a shallow sinus near the extremity. Dorsal areas undefined. 

 Teeth numerous (about eighteen) on each side.* 



* I have not seen the fry of this shell, but suspect it must somewhat resemble a 

 species of which I am unable to procure a specimen, the — 



L. obesa, Stimpson Proc. Bost. Ned. Hist. Soc. iv. p. 113; Shells N. Engl, 

 p. 10, pi. 2,f. 1). — " T. parva, tenuis, oralis, mjeqailateralis, postice lougior, epider- 

 mide nitiila, tenuistriata ; apicibus parvis ; margine vcntiali modice arcuato ; areola 



