Shell large, white, patelliform, oblong, depressed, sides sub-parallel, the shell being slightly broader behind, the ends are broadly rounded and slightly elevated, the anterior slope, which is a trifle longer than the posterior one, is nearly straight, only a little convex towards the subcentral apex in the largest specimen, more convex in the smaller ones, posterior slope slightly concave, more so just behind the apex, side-slopes nearly straight, except for a more or less pronounced compression, at some distance from the apex. Nucleus compressed, subspiral, smooth. The surface of the shell is covered by regular, very fine, concentric growth-striae and irregular grooves, crossed by faint radiating striae, more conspicuous on the rare spots, where a yellowish epidermis still adheres. Interior of shell porcellaneous. In the smaller specimens the posterior slope seems to be shorter, apparently on account of the margin being not intact.
Long 17 mm, lat. 11,5 mm, alt. 5 mm.

The species resembles in many respects C. rathbuni Dall figured in the "Blake Gastropoda', but the new species is less depressed and more elongate. C. laevis Thiele is the nearest ally from the Indian Ocean, but is not as broad, and has more regularly curved sides, being probably much less radiately striated.
The radula has much resemblance with that of C. laevis Thiele, the shape of the rhachidian tooth (R) is really the same, but the upper and side margins are thickened and may be considered as a cusp, the first lateral (1) is much more elongate, not subtriangular, its cusp and that of the second lateral (2) has three denticles, the cusp of the third lateral (3) is simple, the fourth (4) seems to be narrower towards the lower part of the body. The uncini (U) have cusps with a few denticles. The foot has the two epipodial filaments, which characterize the Section Cocculina s. str. of DALL.

Indonesia. Seram, Maluku.