Shell elongate-ovate, elevated, yellowish-white, anterior slope the shortest, nearly straight but slightly convex near the middle, more so near the margin, with a small concavity near the apex, posterior slope conspicuously convex, side slopes irregularly convex. Apex blunt, nearly smooth, save for very fine growth-lines and a few microscopic hairlines; nucleus placed at about 5/18 of the length, deciduous. Sculpture consisting of more or less crowded, slightly wavy, radiating ribs or threads, wanting at irregular spaces; they are crossed by rather regular concentric lirae, slightly stronger than the radii, with very fine striae in the interspaces. Margin rather thick, the whole shell solid, slightly raised in the middle, so that if the shell be placed on a level surface, it rests upon the ends. Inside as far as visible, smooth. Long. 18 mm, lat. 13 mm, alt. 9 mm.

Indonesia. Kalimantan. Selat Makassar.

This shell may easily be distinguished from the only species that by Schepman was known: it is higher with much coarser sculpture, and the posterior slope is much less convex and shorter in proportion to the whole length of the shell. The great depth at which it has been found, together with the external characters of the animal, which has a large head and no eyes, induced me to bring the species to the genus Pectinodonta, which was only known from the western Atlantic. Still I should have hesitated, were it not that the small specimens had produced the characteristic dentition of that genus.