A. E. Verrill—Mollusca of the New England Coast. 217 
Dentalium occidentale, var. sulcatum, nov. 
Shell of moderate size, thin, translucent white tinged with very 
pale yellowish or bluish, moderately curved, more decidedly behind 
the middle, tapering regularly and rather rapidly from the anterior 
to the very slender posterior end. The entire surface is covered by 
well marked, nearly regular, narrow raised ribs with nearly perpen- 
dicular sides and rounded summits, separated by well-defined, 
strongly marked, concave grooves, which are about twice the width 
of the ribs anteriorly, but posteriorly are of about the same width. 
The ribs and furrows show on the interior of the shell within the 
aperture, in reverse, the whole thickness of the shell conforming to 
the sculpture as if they were corrugations of its substance. The oral 
aperture is relatively large and circular, very little oblique, and 
usually with the very thin edge more or less broken. Posterior aper- 
ture very small, usually plain and without any notches, but in one of 
the most perfect specimens it has a slight lateral notch on each side; 
in others there is a small dorsal notch. 
Length of one of the largest specimens, 20°"; diameter at the 
anterior end, 3" ; at the posterior end, *6™", Some specimens are 
slightly more slender than the one measured. 
Station 2076, in 906 fathoms, one living specimen; station 2077, in 
1255 fathoms, four living (No. 35,093), and station 2079, in 75 fath- 
oms, one living specimen. 
This variety resembles D. candidwm Jeffreys in its form and lon- 
gitudinal sculpture, but lacks the transverse lines between the ribs; 
the posterior end is also more slender and more curved than shown 
in his figure. It also closely resembles some young specimens of the 
typical D. occidentale, but the latter has not so strongly marked and 
regular ribs and grooves, nor does the sculpture extend entirely 
through the thickness of the shell so as to appear on the inside, as in 
the present form. Specimens often occur, however, that are evi- 
dently intermediate between the two forms, in the character of the 
sculpture and thickness of the shell. 
Dentalium, sp. ¢. 
Shell small, very slender, considerably curved. Surface covered 
with very numerous, regular, microscopic, longitudinal lines, separated 
by narrower striv. Anterior aperture circular, slightly oblique. 
Posterior aperture very small, squarely truncated in one specimen, 
oblique in the other, without any slit. 
