Shell small, thin, elongated, with a brown opaque sculptured nucleus of three and a half whorls and five and a half (or more) white normal whorls; imperforate, but with a chink behind the inner reflection of the peristome; the later whorls rounded, but with the periphery slightly flattened, giving a faint angulation to the base and posterior aspect of the whorl; the earlier turns do not show this; spiral sculpture between the sutures of some 8-12 flattened strong riblets, with channelled interspaces which grow wider toward the aperture but in general are narrower than the riblets; there are also some faint spiral lines; the apical turn of the nucleus is smooth and slightly asymmetrical, proportionally rather large and inflated, the remainder of the nucleus is strongly marked with flexuous riblets extending from suture to suture; the later whorls are marked with very fine transverse threads, hardly visible, and with thin, short, sharp, somewhat oblique, numerous crenulated or finely fluted varices, partly continuous with those of the preceding whorl and partly intercalary; the margins of the varices, though nowhere spinous, are slightly angulated in harmony with the above mentioned faint angulation of the last whorl or two ; they become obsolete on the somewhat flattened base, which is marginated by a slender elevated thread proceeding from the suture; the peristome is (in the type) not more reflected than the other varices, but may be so in older specimens; the aperture is somewhat oblique and nearly circular. Long. of shell, 8.05; of nucleus, 0.5; of last whorl, 2.75; of aperture, 1.87; max. lat. of shell, 2.75; of aperture, 1.87 mm.

This species has been found off Portugal to the Azores and Morocco at depths ranging from 380 to 1385m. It reaches a maximum size of about 15mm. It has about 8 teleoconch whorls with numerous serrated costae and about 15 spiral threads per whorl. The costae and spiral threads continue across the base of the shell. The whorls are angled about 1/4 of the distance below the suture and the umbilicus is open. The 3.5 protoconch whorls are axially ribbed. The aperture is round and the outer lip is thin.

The nucleus in this species is markedly different from that of any of the other forms I have examined, not only in its relatively strong and peculiar sculpture, but in its solid and opaque consistency and deep color. I have referred this shell to Jeffreys's species with some doubt. The fragments which represent his shell in the Jeffreys collection are much more drawn out, and can hardly be the same thing; but the figure in the P. Z. S., though still somewhat more slender than the Blake shell, is intermediate, and I do not feel justified under the circumstances in proposing a new specific name for the latter. I retain, however, the diagnosis and figure, which were prepared before the publication of Dr. Jeffreys's paper, as perhaps serving to throw a little additional light on the subject.

Florida, off Tortugas Keys.