MUSEUM OF COMPARATIVE ZOOLOGY. 207 
canal. The shoulder of the whorls, situated at the periphery, is ornamented 
with rather broad, slightly angular, oblong, oblique nodules, thirteen on the 
penultimate whorl, separated by slightly concave, about equally wide spaces. 
The entire surface, except the subsutural band, is covered by raised, rounded, 
revolving threads of nearly uniform size, which extend over the shoulder a 
little way on the subsutural band, where they are a little finer and closer 
together than elsewhere. 
Length, 22 mm.; breadth, 8 mm.; length of aperture, 10 mm. 
Pleurotomella sulcifera, sp. nov. 
Plate Il. Fig. 4. 
One living specimen, Station 325, off Cape Fear, N. C., in 647 fathoms. 
Shell rather large, fusiform, rather thin, translucent white with very little 
lustre. It has a high, regularly tapered spire of six obtusely shouldered whorls, 
not counting the nucleus which is broken off, and a long, nearly straight colu- 
mella and a broad, straight aperture occupying about half the length of the 
shell. Posterior sinus as broad as the subsutural band, shallow, slightly 
broken. Outer lip thin, curving very gently to join the columella with but 
a very slight bending in anteriorly, not forming a well-defined canal. Colu- 
mella with a thin, narrow strip of enamel extending its entire length. Suture 
inconspicuous. Subsutural band rather broad, oblique, crossed by delicate 
slightly curved riblets, most distinct on the upper whorls. Narrow, oblique, 
angular ribs, fifteen on the body whorl, separated by rather deep, narrow 
spaces, cross the whorls, rising just above the periphery and not quite reach- 
ing to the suture; these are cut just above the middle by a broad, shallow 
groove, making them appear, especially on the body whorl, as two rows of 
nodules. In some positions of the shell there seems to be a second similar 
groove (scarcely discernible) below this oné. The spiral sculpture is very ir- 
regular. On the body whorl, below the transverse ribs, there are from twenty- 
five to thirty shallow grooves, varying in width, and having between them 
flattened bands or threads. On the canal they are so close together that their 
interspaces appear like rounded threads ; above these, about the middle of the 
whorl, they are very broad, and separated by equally broad flattened bands, 
while still above these, below the ribs, they are again narrowed and separated 
by flattened threads. On the ribs the grooves also vary considerably. On each 
side of the principal groove, a rather broad, flattened thread forms a slight crest 
on the summit of the ribs, and beyond the lower one of these there are two 
or three fine rounded threads. The principal groove is also interrupted by a 
rounded thread at about the middle, and two or three very faint ones above 
and below it. On the upper part of the ribs there are two or three unequal 
grooves. On the penultimate whorl there are four grooves below the princi- 
pal one, separated by nearly equal spaces, with but a single rounded thread 
on the centre of the first or principal one, With the exception of the subsu- 
