Diagnosis: Shell slender, fragile, conoid in initial whorls and cylindrical in later ones. A well-defined umbilicus is surrounded by a distinct prominent spiral ridge. Sculpture of weak axial ribs also covering the spiral ridge.
Description: Shell cylindric-conoid elongate with a sharp apex, fragile, slightly translucent and whitish. Protoconch small in relation to the size of the shell, of type B tending towards A (in the classification of AARTSEN, 1987), planispiral and 250 mu in diameter, showing one whorl with visible nucleus partially sunk into teleoconch. Teleoconch beginning with 5 or 6 smooth whorls, increasing quickly in diameter giving the shell a conical shape. Thereafter numerous axial riblets appear, weakly marked and slightly irregular. The subsequent 1-2 whorls increase regularly in diameter but the following keep the same diameter giving the shell a cylindrical profile. The last whorl represents one-third of the total shell length and has a strong cord surrounding the umbilicus near the base. Umbilicus is narrow but deep. The cord is present also in juvenile shells, being then less marked, and becoming stronger with growth. Aperture is semicircular and slightly pyriform. The visible part of the columella is slightly undulating and without any fold. Columellar fold is visible in juvenile specimens, and a well-demarcated prominent fold is present on the internal part of the colu-mella in broken shells. Outer lip is smooth, narrow and without any folds. The curvature is slightly irregular, extending both to the base and to the external part of preceding whorl. The micro-sculpture is not readily visible in the initial teleoconch whorls, but a rough surface is visible in high magnification in the following whorls. This surface is formed by many microscopic depressions. In the subsequent whorls there are axial undulations between and on the axial ribs.
Dimensions: The holotype is 14.3 x 3.8 mm.

This is a rare species. Shells and shell fragments have been found from Mauritania to Angola.