290 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
three-whorled, white, polished, with a peripheral carina on the third whorl 
which terminates abruptly ; subsequent whorls four and a half, strongly sculp- 
tured; suture distinct, simple; whorls with 12-14 strong axial, slightly pro- 
tractive ribs, faint on the anal fasciole, strong at the shoulder, and gradually 
attenuated over the base; these are crossed by (on the last whorl about fourteen) 
strong, subequal, equidistant channelled sulci, absent on the fasciole, obsolete in 
the depressions between the ribs, but cutting the summits of the ribs into squarish 
nodules; the fasciole is smooth and polished, but shows about four alternate 
opaque and translucent spiral bands of white, which at first look like threads ; 
aperture narrow, anal sulcus strong, not deep, surrounded with a heavy callus ; 
outer lip callous, forming a heavy varix, with six or seven internal lirae strongest 
and dentiform at the margin; body with a heavy and prominent anal callus sepa- 
rated by a gap from eight or nine dentiform lirae on the straight pillar; canal 
short, wide, at the anterior margin flaring. Lon. of shell, 10.4; of last whorl, 
7.0; of aperture, 6.0; max. diam. 5.0 mm. 
U.S. S. “ Albatross,” station 3391, Gulf of Panama, in 153 fathoms, mud, 
bottom temperature 55°.8 F. U.S. N. Mus. 123,115. 
I do not feel certain that the existing nuclear shell is not an internal cast of 
a very thin, perhaps differently sculptured, larval shell, of which in one specimen 
I fancy traces are visible near the suture. 
Glyphostoma thalassoma Datt, n. sp. 
Shell slender, acute, eight-whorled, beside a nucleus of about a whorl and a half; 
the spire longer than the aperture, whorls gently rounded, suture appressed, not 
deep ; axial sculpture of (on the penultimate whorl twenty-one) feeble, narrow, 
protractive ribs, concavely arcuate where they pass over the anal fasciole, and at 
the other end becoming obsolete on the base of the whorl, their interspaces 
narrower or subequal to the ribs; these are crossed by (between the sutures five 
or six, on the last whorl about eighteen) rounded, equal, strong spiral threads, with 
narrower interspaces, and hardly enlarged where they intersect the ribs; the anal 
fasciole is rather obscure and sculptured with incremental lines, and on the ante- 
rior edge about three very fine spiral threads; on the canal beyond the major 
threads are about fifteen minor spirals closely crowded; outer lip with a strong 
varix and conspicuous rounded anal sulcus, behind which on the body is an areu- 
ate mass of callus; edge of the outer lip thin, strongly lirate within, the anterior 
margin denticulate; inner lip thinly callous, with a marginal row of small pustules 
opposite the lirae; canal constricted, deeply sulcate, somewhat recurved ; shell 
discolored, probably originally whitish. Length of shell, 19.5; of last whorl, 12.0; 
of aperture,.9.0; max. diam. 6.5 mm. 
U.S. 8. “ Albatross,” station 3017, off Cape Lobos, Gulf of California, in 58 
fathoms, mud, bottom temperature 61°.8 F. U.S. N. Mus. 110,612. 
It is possible that, with greater age, the armature of the inner lip might be 
more conspicuous, as the shell may not be completely mature. 
