Q74 Marine Shells of Massachusetts. 
which is always highly arched, and is produced beyond 
the plane of the aperture,—in the length of the spire,— 
in the longitudinal ribs, which are usually less distinct 
on the body whorl,—and in the color, which, in the 
young, is a uniform reddish black, and which becomes 
reddish cinereous in weather-worn specimens ; while in 
the mature shell the depth of color diminishes from the 
upper whorls, often passing into a pale horn color, 
sometimes white, on the lower whorls, regularly macu- 
lated on the revolving ribs with rufous or brownish. , 
Length,-.28 in.; breadth, .11 in.; of a specimen, 
rather more: elongated than usual, length .23 in. ; 
breadth, .085 in. : 
The operculum is horny, ovate, concave externally, 
but with an irregular surface, multispiral ; apex in the 
centre of the broader part; whorls four to five, very 
convex on the under side. The operculum is small, 
and drawn far within the shell. Length, 05 224 
breadth, .04 in. 
"This species is very shinite at Nantucket, New 
Bedford, and vicinity, and has been found by Dr. Gould 
» as far north as Provincetown harbor, on Cape Cod. In 
the description of the species, Boston harbor is men- 
tioned as a locality. I have not been able to find it, and 
am not aware that the frequent and very careful search, 
e which. has. been made for the marine shells in our 
*., neighborhood ars two or three years past, has de- 
tected it. bab y Cape Cod is the limit, to the north 
of which it will rar arely be found. 
Inthe spring, the young of this species are often pas 
ore in such numbers as to conceal the 
"lying on the sho 
d and beneath tein, wiioagh few, if any, are mature. 
