This is a small species with a very characteristic colour pattern, except in the Philip-pines where it is polymorphic (pers. obs.); it is common and often found in large numbers. It is, however, occasionally confused with other species in the literature; Wilson (1994) shows a drawing of M. moleculina as his figure of Mitrella venulata (Sowerby, 1894). Higo et al. (1999) place this species in Metanachis, however it lacks any axial sculpture, columellar folds, or aperture denticles that would support that designation.
The shell is typically 4.5 to 6 mm long (though may be rarely up to 7.5 mm) with about 4 teleoconch whorls. The aperture is almost half the shell length. The shell has a base colour of white overlain by a broad band of yellowish tan. Over the middle of the body whorl there is a band of large, closeset round white spots. There is an additional row of alternating small and large white spots just below the suture. Below the smaller white spots there is a narrow dark brown stripe, interrupted by the larger spots so that it becomes a series of dashes. There is also a brown band at the base of the shell interrupted by large white spots. The base of the shell has wavy chestnut axial markings. The aperture is white, with denticles on both the labial edge and usually four large denticles on the parietal wall. The protoconch is usually white, often with a brown suture, and wider than the first teleoconch whorls; it is smooth, and has 3.75 to 4 whorls.

Shell solid, fusiform; base truncate. Protoconch: weakly tilted, of about 3 smooth, strongly convex whorls; last whorl strongly globose; suture deeply impressed. Teleoconch: of about 4 smooth, flat sided to weakly convex whorls; last whorl inflated, contracted towards the base, with some weak spiral cords at the base; suture faintly impressed. Aperture: moderately wide, peristome continuous; outer lip weakly thickened externally with a broad varix; inside of outer lip with 3 strong posterior teeth and usually with 3 weak anterior denticles, the latter sometimes lacking; inner lip thin; columella with 3 prominent denticles on the outer margin; siphonal canal narrow, very short, weakly bent; siphonal notch deep; posterior canal moderately deep. Colour: yellowish-white with a network of brown-orange lines; subsutural brown streaks alternating with white dots, and white dots above each brown streak; below these markings a network of brown lines with connected comers. Radula: each radular row consisting of a subrectangular median tooth, flanked at each side by one tricuspid lateral tooth; the uppermost cusp of the latter long and pointed, the median short, subtriangular and the lowest one slightly longer than the median, but shorter than the uppermost one.

This species, although characteristically figured in the above unfinished monographs, has not, I believe, been as yet described. It is small, ovately fusiform, glossy, white, covered with a network or connected circles of a yellowish-brown colour, varied with two interrupted dark-brown transverse lines, one at the upper part of the whorls a little below the suture, where the ground-colour is at times opaque snowy white, and the other, consisting of less elongate spots, round the base of the body-whorl. Volutions 8, smooth, three apical convex, the rest nearly flat at the sides, very faintly gradated; the last rounded at the middle, contracted beneath, and strongly transversely grooved at the extremity. Aperture small, contracted into a short oblique canal in front. Outer lip strengthened with a remarkably broad external varix, distinctly sinuated a little below the suture and armed within with six small denticles, of which the second and third below the sinus are usually the largest. Columella covered with a callus bearing three or four elongate transverse tubercles at the lower part. Length 6 mm., width 2,3 mm.
This pretty little species must not be confounded with C. galaxias Reeve (Conch. Icon. figs. 229 a, 6). The latter has a similar interrupted line at the upper part of the whorls, and an indication of a second towards the base of the last, but is nevertheless quite distinct, being destitute of the roundly meshed network, and more elongate in form. It has an opaque-white dotted line immediately above the suture falling round the middle of the body-whorl, and consists of two more normal volutions than C. moleculina.