Shell of medium size, conical, slightly turreted, white. Protoconch of less than 1 whorl, nucleus large, immersed in the summit. Mature whorls 7, short, only slightly rounded, with a slight shelf below the sutures, particularly on the early whorls. Sculpture of axial ribs, 14-16 on the early whorls, where they are well defined and rounded, but much weaker on the penultimate, and practically obsolete on the body whorl, which is nearly smooth. Spiral sculpture absent. Aperture ovate, angled posteriorly, slightly oblique and thrust forward anteriorly, outer margin expanded and thin with a very slight external varix, columella bent backwards with a small shallow sinus. Length 6-2 mm.
Locality.-^—Thursday I. (J. Laseron), holotype and 2 paratypes.
Remarks.—This was easily separated from M. artensis, with which it was associated, by being less than half the size, by the greater persistence of the axial ribs, and by the less oblique aperture.