Marine Shells of Massachusetts. 319 
' Shell small, thick, ovate-fusiform, cinereous brown 
through (and light or dark brown beneath) the 
epidermis ; epidermis membranous, thin, dull, cine- 
reous; whorls six to seven, convex; suture deeply 
impressed ; spire five-ninths of the length of the shell, 
longitudinally and coarsely plicate below the first or 
second whorls (which are smooth), decussated by 
transverse small ribs or coarse strize ; body-whorl lar- 
ger than the spire, sculptured as the upper whorls, 
with 10 to 12 longitudinal ribs, extending to the ca- 
nal, either continuous or alternating with those on 
the penultimate whorl, with 13 to 15 transverse striæ 
on the back of the body whorl, oblique on the canal, 
very oblique on its left side ; aperture elongate-ovate, 
the line of its length at an angle of about 30° with 
the axis of the shell, four-ninths of the length of the 
shell; Jabrum brown or: yellowish-brown internally, 
sonnei talk arcuate, much thickened by the last plica- 
tion, beneath which is a groove, reaching from the 
sinus to the canal, and sharpening the edge; sinus a 
little below the junction of the labrum with the last 
whorl, rounded and broad at the bottom, occupying 
one-fifth of the length of the labrum, in mature speci- 
mens nearly as deepas broad ; canal short ; columel- 
la somewhat excurved, acutely terminated ; labium 
in its upper third arching over to meet the labrum ; 
umbilicus wanting ; operculum unknown. 
Average | size ; length, .5 inch; breadth, .25 inch ; 
largest specimen, .52 inch by 21 inch. 
Cabinets of the Bost. Soc. Nat. Hist., of Middlebu- 
TY College; of Mr. C. F. > of New Bedford, 
and die own. 
