Shell small, patelliform, oval, depressed, pellucid, white, with small patches of a thin, yellowish epidermis; ends broadly rounded and elevated; anterior, posterior and side-slopes convex, with only a slight depression behind the depressed apex. Nucleus very much depressed, compressed, scarcely spirally striated under a lens, but under the microscope the nucleus is covered by rows of conspicuous alveoli (much more conspicuous than in the preceding species). It is placed at about 5/9 of the length of the shell, the front slope being the largest. The sculpture consists of conspicuously elevated concentric striae, of which a few are stronger than the rest, they are crossed by radial striae, which are but slightly weaker, a little waved and make the concentric striae slightly beaded, especially the stronger ones. The shell is still more cancellated than in C. ovata. Inside shining. Foot of the animal with epipodial filaments.
Long. 4,5 mm, lat. 3,25 mm, alt. 1,5 mm.

This species differs from the C. ovata, by its depressed apex and stronger sculpture, moreover by the convex slopes and the much larger pits or alveoli of the nucleus, this character being not visible in C. ova ta with the same lens as in the present species.
I examined the radula of one of the specimens. This agreed in every respect with those of the other species of Cocculina, examined by THIELE and by me, but the median tooth wanted; as however the shell-characters and the animal agree very well with the other species, I think the radula will be only abnormal. The first and second laterals (1, 2) have three denticles at their cusps, that of the third (3) is simple and the fourth (4) has the same characters as in the preceding species, being however broader, the uncini have small denticles. The peculiar sculpture of the shell, seemed at first to be favourable to generic separation, but it is connected to those species with smooth nucleus, by the preceding species.

Indonesia. Saleh-Bay. North coast of Sumbawa.