Shell translucent white, elongate-conical, extremely acute, with granulated surface and about twenty-four somewhat rounded whorls ; nucleus extremely minute and partly submerged, smooth, shining, translucent, passing imperceptibly into the very attenuated shining apical whorls, which in the adult are most frequently, though not always, lost; spiral sculpture in the earlier whorls of two rather strong subequal rounded revolving riblets, to which, about the seventh whorl, another smaller thread just before the suture is added, which soon becomes nearly as prominent as the posterior riblet of the original pair; the space between the original pair gradually grows proportionately wider, and about the tenth whorl a fine intercalary thread appears which always remains smaller than the others; beside this in the nearly adult shell the space between the original anterior riblet and the suture (to which this part of the whorl rapidly descends) is supplied with two very fine elevated threads; a similar one may also (but does not always) appear intercalated between each pair of the four principal spirals above described ; on the base in the fully adult eight or more subequal simple spirals appear between the periphery and the canal, while the more anterior original spirals diminish in prominence and gradually approximate in size to the basal ones; in the younger shells the difference is quite strongly marked. The transverse sculpture in the apical whorls consists of a few (six or eight) rather strong trans¬verse riblets, which appear as stout rounded tubercles on the spirals, and run down the spire almost straight, until the order is broken up by the continual appearance of new intercalary series (seventeen on the thirteenth whorl and about twenty-two on the last whorl); on the later whorls these are somewhat concavely flexed, and no regular succession up and down the spire can be made out; fine lines of growth appear on the anterior whorls, which by the constriction of the basal periphery put on a rather rounded outline, so that the number of whorls can be easily counted, though the suture is almost invisible ; on the base the only transverse sculpture is due to the delicate lines of growth ; the last whorl or two may have one or two faint varices ; the base is flattish in the young, rounded in the adult; the outer lip expanded and thickened concave behind, basally produced and curving into a distinct but not produced canal, which opens to the left; on the other side the outer lip is continuous with a thin but distinct callus, which is twisted over the very short and inconspicuous pillar ; the rejected edge of this callus is not adherent to the pillar, and there is a perceptible chink under it, or more properly above it; the aperture is subovate, pointed before and behind. Lon. of shell, 16.0; of last whorl, 3.62 ; of aperture (from point to point), 2.5. Max. lat of shell, 3.0 ; of ap¬erture, 1.75 mm.

Shell elongated, with twenty or more whorls, the tip of the nucleus being lost; there are three revolving rows of strong tubercles, that just below the suture being smaller than the other two; the two principal rows somewhat widely separated and having sometimes an intermediate, nodulous thread; columella slightly twisted; canal scarcely truncate below; base with fine, revolving line. Color white.
Length, 16; diameter, 2.25 mm.