Holotype: Shell 15 mm (about 0,5 inch) in length, solid, elongate-ovate, sutures distinct but sharply incised and irregular on the dorsal side of the body whorl. Whorls 6, apex missing, spire whorls regularly convex, first 3 whorls clathrate with bisecting spiral and axial cords of about equal strength; the spiral cords weaken and axial cords become obsolete on the last 3 whorls. Spiral striae number 7 on the penultimate and 15 on the body whorl, apart from 10 oblique cords at the base. The dorsal side of the body whorl has 4 wide-spaced growth-striae. Aperture about equal in height to the spire, narrow and smooth within; outer lip thickened and simple. Columella slightly calloused and with 6 prominent, oblique folds. Siphonal fasciole twisted and slightly reclined to the left, siphonal notch prominent. Colour white in the beach-worn type, sutures of the last 3 whorls with small, brown spots.

Philippine Islands and Japan.On the reefs, low water.

The holotype remains the only specimen known. Subsequent literature records are repetitions of the original description, and no specimens resembling the species have been collected since the date of description. We strongly suspect that M. bellula is a very worn, atypical or aberrant form of a previously described species; the cancel late upper whorls and general shape bear a faint resemblance to Mitra (Strigatella) pellisserpentis Reeve. A. Adams (1864) subsequently reported the species from Japan, but assigned it to the vexilline subgenus Costellaria; even in its worn condition it is obvious that the species is mi trine and not vexilline, and Adams' Japanese specimen may have been something different.