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—a, enlarged—s, 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 shghtly 
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 labrum: 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—4, 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. 
JVote.—The crenulation on the inner margins of Venus gemma, and the fold on 
the columella of Acteon trifidus, have been omitted by the engraver. 
