86 
their under surfaces give off five of the buttresses of the apertural 
iamina. About five small tubercles continue the series posteriorly 
on the proximal part of the variceal tube. Operculum horny, 
ovate, nucleus apical anterior. Ornament, in very young speci- 
mens, a chestnut-brown spiral line at the base of the variceal 
- tube, and a second about the level of the lower end of the 
aperture. 
Length, 14:25; breadth, 5°5 between the varices, 7 including 
them; spire, 6; body-whorl, 8:25; length of aperture, 3; width, 
2; length of canal, 3°75 mm. 
Habitat.—Backstairs Passage, 22 fathoms, three alive, and 
St. Vincent’s Gulf, dredge siftings, ? depth or exact locality, 25 
dead and alive of various sizes (J. O. Verco). 
Type specimen in my collection. 
It bears a superficial resemblance to I. Angasz, Crosse, but 
this is a narrower thinner shell, with a single curved (not 
sinuous) and open posterior variceal hook, an open anterior canal, 
and a simple aperture. 
This shell resembles a Z’yphis in its sinuous posterior tube ; 
but the variceal origin of the tube separates it from all the 
species of that genus, in which the canal is inter-variceal. 
Tt differs from 7’. triangularis, A. Ads., in the absence of spiral 
lire, and the closed straight canal. From 7’. Japonicus, A. Ads., 
=T". arcuatus, Hinds., in having no arched varices, no pseudo- 
varices, and its tubes not truncated From Z’. cancellatus, Sow., 
in the very narrow varices along the canal. 
Pe 66 
LB a feaminan angustus, sp. nov. Pl. i., fig. 7, Ba. GY 
Shell fusiform, sordid-white, lamellosely varicose ; whorls six or 
seven, including the nucleus. Nucleus one turn and a-half, 
smooth, polished, blunt. -Spire subturreted, whorls moderately 
convex, varices slightly higher than wide, six in each whorl; two 
or three broad obsolete spiral lire, most marked just beyond the 
varices. Body-whorl slightly convex, contracted somewhat an- 
teriorly ; about five broad subraised spiral lire, with two to five 
intervariceal longitudinal lire, dividing the intervariceal areas 
into square spaces of varying size. Varices six, sinuous, pos- 
teriorly shortly convex to the right, straight in the middle, 
anteriorly openly and markedly concave to the right, in apposi- 
tion over the dorsum of the canal; the last-formed rather higher 
than wide, but easily worn down; so that the earlier ones are 
wider than high, higher and narrower anteriorly. Aperture 
elongate-ovate, enamelled internally; outer lip varicose ; ° 
columella arcuate, distinctly angled at junction with canal; 
inner lip thin, anteriorly slightly separate from columella, and 
very slightly curving over the canal; canal bent to the left, 
