Shell very small, white and shining, ovate, narrower in front, spire minute, but distinct, of about two turns. Aperture rather narrow, widening gradually towards the front. Columella slightly convex, and bearing three fairly equal plications. The outer lip rises below the spire, and is only slightly shouldered; it is strongly thickened and simple.
Length 2 mm Breadth 1.2 mm.
Type, with a number of others, in 40 fathoms, off Thouin Bay, Freycinet Peninsula, also from C. Pillar, 100 fathoms, and other places, including the Furneaux Group. Related to M. connectans, May, but is only half the size, less cylindrical, with more spire, and three equal sized plaits.

Locality.—Thirty to fifty fathoms off Sydney, the specimen figured 1-8 mm. in length. This is a minute, colourless, glassy shell, and may be recognized by its three columella plaits and high aperture. It agrees very well with May's freycineti, which is a common Tasmanian deep-water shell, and thus is a new record for New South Wales.
A broader variety, but otherwise indistinguishable, is from 30-35 fathoms off Crookhaven, length 2 mm. A longer series is necessary to determine whether the differences are sufficient to be considered specific.