24 PHILINE. 
Of Bahia Honda, Cuba, in 220 fms.; near St. Kitts in 245 fms., 
sand ; off Gaudelupe in 175 fms., sand; off Dominica in 372 fms., 
sand ; off Dominica 138 fms., near Barbados in 118 to 209 fms. 
Bottom temperatures ranging from 48° to 64° F. 
This seems to be a rather common species from the frequency with 
which it was taken. It differs entirely from P. sagra Orbigny, and 
is wider and squarer than P. candeana Orb., in which, moreover, 
the spire is represented as visible for two turns at the apex. (Dall). 
P. pLanatTa Dall. Unfigured. 
Shell resembling that of P. aperta Linné, but flatter, smaller, 
more quadrangular, with a shorter and smaller body whorl, more 
polished surface, and with an impressed spiral line near the apex 
which extends to the margin, where it marks a slight sinus, behind 
which the posterior margin is prolonged into a rounded prominent 
point. The shell is brilliantly polished and smooth except for lines 
of growth, but near the apex are a few microscopic faint spirals 
invisible without a lens. The spire is wholly immersed and makes 
in all about one and a half turns. The ventricular plates are 
formed like those of P. infundibulum, and not like those of P. aperta. 
The outer surface of the right plate has two longitudinal blackish 
lines. The two small plates are somewhat more arched than in P. 
infundibulum. The inner or triturating surface is similar in both. 
The length of the largest shell observed is 11°5 and its breadth 
9°0 mm. 
The soft parts are in general much the same as in P. aperta, but 
the cephalic lobe extends farther back and the foot is rounder, flat- 
ter and less rolled up at the sides. As seen from below the body 
whorl of the shell equals only about one-sixth of the total width. 
Off Dominica in 138 fms. ; off Barbados in 140 to 209 fms., bottom 
temperature 50° to 56° F. 
The species is readily distinguished from any other of the group 
by the posterior point, which, though smaller, recalls that of Cheli- 
donura Adams. The soft parts, however, have no resemblance to 
the very peculiar figure of Quoy and Gaimard. _P. amabilis Ver- 
rill is much nearer P. aperta, from which, as far as the shell is con- 
cerned, it chiefly differs by being a little narrower than the average 
aperta. ‘The species are, however, quite variable in this respect. 
(Dall. Blake Gastr., p. 58). 
