Description of some New Shells. 369 



Inhabits Plymouth harbour, (Mass). This shell has a somewhat 

 pearly lustre, and is feebly iridescent. We have, as yet, seen no 

 Turbo on this coast of which this can be the young. 



T. minutus. 



Fig. 6 — tf, enlarged — 6, natural size. 



Shell small, conic, thin, translucent : whirls about six, convex, 

 faintly striated transversely : spire gradually tapering to near the apex, 

 then suddenly obtuse : suture impressed : mouth more than one third % 

 the length of the shell, oval, entire, rounded at the base, angular 

 above : outer lip sharp : lower portion of the columella lip slightly 

 recurved ; a calcareous deposit connects the lips, and, in adult spe- 

 cimens, rises above the surface of the shell, forming a prominent con- 

 nection of the labium with the iabrum : color brownish-yellow, or 

 horn color, immaculate : within whitish : operculum horny. 



Length, 0.13 of an inch. 



Greatest breadth, 0.08 do. 

 Inhabits coast of Mass. and R. I. 



Genus Pasithea, Lea. 



P. nigra. 



Fig. 7 — a, enlarged — £, natural size. 



Shell small, acute-conic, turrited, thin, black : whirls about eight, 

 flat, having a distinct shoulder, and made to appear granular by four 

 equal, raised, rounded, revolving lines, filling the space between the 

 sutures, these lines being cancellated by numerous equal lines which 

 are longitudinal as respects the shell — inferior portion of the body- 

 whirl not cancellate, occupied by about six slightly raised revolving 

 lines : spire acute-conic : suture deeply impressed : mouth more than 

 one third the length of the shell, elongate, sub-ovate, acutely angular 

 above, widely rounded below, and slightly effuse at the base : a thin, 

 glossy-black calcareous deposit connects the lips : outer lip without 

 a sinus, not thickened, and faintly modified on its sharp edge by the 

 raised revolving lines : operculum horny. 



Length, 0.15 of an inch. 



Greatest breadth, 0.08 do. 



Inhabits the shores of Rhode Island. Found with Acteon trifidus 

 adhering to Pecten concentricus. I know no group in which this 

 shell can be so well placed as in the above new genus of Lea. 



Note. — The crenulation on the inner margins of Venus gemma, and the fold on 

 the columella of Acteon trifidus, have been omitted by the engraver. 



