146 A. FE. Verrilli— Mollusca of the New England Coast. 
Length of the body and head, to base of arm, 27"; length of 
body to edge of mantle above, 20"; breadth across body, 14™™ ; 
breadth of head across eyes, 11™™; diameter of eye-ball, 4:5™™; 
length of dorsal arms, 7"; length of second pair of arms, 9™™ ; length 
of third pair, 14"; length of ventral arms, 7°5™"; length of hecto- 
cotylized arm, 11"; height of largest specialized suckers, 3™™ ; 
diameter, 3™™. 
Station 2099, N. latitude 37° 12' 20”, W. longitude 69° 39’, in 2949 
fathoms, (No. 35,268 *). Steamer Albatross, 1883. 
GASTROPODA. 
Pleurotomella Verrill. 
Amer. Jour. Science, v, p. 15, 1882; Catal. Marine Mollusca, these Trans., v, p. 
453, 1882. ' 
This genus was originally proposed for P. Packardii, first taken 
in deep water in the Gulf of Maine. This species is remarkable for 
the delicacy and beauty of its sculpture and the great depth of its 
subsutural sinus. The subsequent discovery of numerous other 
related species inhabiting the deep waters, off our coast and in other 
regions, has rendered it necessary to enlarge the limits of the genus 
and to modify its characters. 
As at present understood, this genus is intended to include those 
species which have a rather broad and very distinct subsutural band, 
crossed by excurved lines of growth corresponding to the form of the 
posterior sinus of the lip, which is situated a little below the suture 
and is always pretty well-developed, but is sometimes broad and 
shallow, and at other times narrower and very deep. The outer 
lip is always thin and sharp, without any appearance of a varix, nor 
is there any deposit of callus on the body-whorl, in front of the aper- 
ture. The canal is well developed, generally constricted at the base 
and somewhat elongated, and usually but slightly curved. Ina few 
of the species, doubtfully referred to the genus, it is short and wide. 
The columella-margin is more or less sinuous. The nucleus differs in 
sculpture, and usually in color, from the rest of the whorls, and is 
generally minutely cancellated by fine raised lines running obliquely 
in opposite directions. The remaining whorls are elegantly sculp- 
tured by longitudinal ribs and revolving cinguli, and usually have a 
distinct shoulder or carina, which is frequently nodulous, below the 
* The numbers given in this paper are those used in the permanent catalogue of the 
mollusea, in the National Museum. : 
