Shell small, elongated, with turriculate and scalate spire. Dimensions: up to 18.7 mm high and 9.7 mm wide (Senegal, Rufisque; RMNH). Colour white to pale brownish, sometimes with a single or double pale-brown spiral band at about 1/3 of the height of the whorl, and one on the last whorl, just posterior to the second carina; narrow dark brown blotches near the suture between the axial ribs on the posterior part of the whorl. Protoconch paucispiral, fawn to pale brown, slightly inclined with respect to teleoconch axis, almost without sculpture, sometimes a few faint growth lines.
Teleoconch with up to 5 1/4 whorls. Suture deeply impressed. Axial sculpture very marked; number of axial ribs on lst-5th whorl: 1st, x = 10.88 (a = 0.71, n = 34); 2nd, 9.74 (a = 0.89, n = 34); 3rd, 9.38 (a = 0.94, n = 29); 4th, 9.44 (o =1.82, n = 15); 5th, 5 (n = 3). Spiral sculpture mostly rather diffuse, especially on the younger whorls; number of spiral ridges (including secondaries) on lst-4th whorl: 1st, x~ = 3.85 (o = 0.53, n = 27); 2nd, 5.17 (o = 1.17, n = 29); 3rd, 8.32 (o = 2.85, n = 22); 4th 9.16 (o = 2.99, n = 6). However, two spirals are well marked: the one on the shoulder of the whorl is narrow but relatively high; and the spiral in the prolongation of the sutural line on the body-whorl is quite conspicuous: this may confer to the aperture a somewhat trapezoidal from. The spirals are best visible when crossing the axial ribs; in the areas between these ribs they are often very faint. The teleoconch has a microsculpture of tiny pits.
Aperture trigonal to trapezoidal; no lirae inside outer lip; no parietal teeth. Columella straight, parallel to shell axis, with two folds (which may be brown), posterior one the strongest. The rim of the siphonal canal might be interpreted as a third fold (the original description of Tribia mentions "trois plis peu saillants"); in young shells this rim almost coincides with the anterior fold. Siphonal fasciole poorly developed. Umbilicus closed in younger specimens, in older ones it is half covered by a whitish to brownish callus.
As far as could be judged on a dried specimen, the animal had the foot speckled with reddish-brown dots.

Mauritania, Senegal, Sierra Leone.