Shell size small for genus, adult size up to ca. 3.2 mm; fusiform, bulbous. Suture slightly impressed. Protoconch paucispiral, -1.5 smooth whorls. Teleoconch of little less than three whorls. Axial sculpture absent. Spiral sculpture of basal cords, ventrally ranging to just below adapical end of columella. Outer lip thickened, with distinct rim, smooth, bearing only continuation of basal cords. Inner lip denticulate, with four very weak denticles. Columellar callus raised, clearly demarcated. Parietal callus weak. Columella smooth. Siphonal canal short, open, slightly recurved, markedly longer on columellar side. Teleoconch whorls off-white in colour, semi-translucent. Protoconch off-white, semi-translucent. Aperture and columella ofT-white. Holotype height 2.9 mm.

This species is most similar to M. parvicosta, but differs in its lack of shouldered whorls, smaller teleoconch, lack of both spiral and axial sculpture, weaker denticles on inner lip, smooth columella and in the shape of the siphonal canal.

New Caledonia: Norfolk Ridge, 401-650 m.