A. E. Verrill—Mollusca of the New England Coast. 435 
is thin, but bears, just in front of the beak, a large, strong, crescent- 
shaped tooth, convex within, projecting upward nearly at right angles 
“to the margin, and hollowed out on its upper side, at the lunular 
depression, so that the entire thickness of the tooth is situated within 
the outline of the edge; another very much smaller, triangular tooth 
is situated under and behind the beak, within and below the margin. 
The exterior ligament is small and thin. 
Length, 8"; height, the same. 
Station 2,229, off Chesapeake Bay, in 1,423 fathoms. One dead 
specimen (No. 44,838.) 
Tapes, sp. 
At station 2,206, in 1,043 fathoms, a single, somewhat eroded left 
valve of a Zupes was dredged, which agrees very closely in size, 
form and general appearance with Z. virgineus of Europe. It is, 
perhaps, a little more oblong, or less convex ventrally, and the con- 
centric ridges are finer, closer, and less raised, or more like lines of 
growth. The hinge-margin is thicker and stronger. The pallial 
sinus is smaller, narrower and more pointed. 
Length, 38"; breadth, 22™™ (No. 40,108.) 
Choristodon (?) cancellatus Verrill, sp. nov. 
Shell rather small, swollen, triangular-ovate, with the umbos prom-— 
inent and swollen, and the beaks large, subspiral, and turned forward, 
so that in a front view the shell has a strongly cordate form. The 
anterior end is short and broadly rounded; the posterior end is 
longer and narrower, somewhat tapered, obtusely rounded at the 
end. ‘The posterior dorsal margin slopes rapidly, and is subparallel 
with the ventral margin. There is a small, depressed, distinct, but 
not much differentiated lunular area in front of the beaks. The 
sculpture consists of numerous narrow, nearly equal, sharply cut, 
radiating grooves, separated by wider raised ridges, which are 
decussated by thin, sharp, raised, concentric lines; these two sets of 
lines, in crossing each other, produce a rather fine cancellated strue- 
ture over the entire surface. The hinge consists of two strong cen- 
tral teeth just below the beak, separated by a triangular pit, and 
supported on a rather broad plate, extending inward from within 
the thickened margin; the posterior of the two teeth is largest and 
thickest, and may have been slightly bilobed when perfect. A thin, 
incised ligamental groove runs from under the beak backward ina 
curved line between the thickened inner and outer shell-margins. 
Muscular and pallial scars are not visible, owing to erosion. 
