Shell small, suborbicular, thin, depressedly convex, white; nucleus subcentral, but placed a little at the posterior part, smooth, spiral; a zone around the nucleus is sculptured by fine radiating striae, the remaining part of the surface is sculptured by strong radiating ribs, about 23 in number, separated by rather deep grooves or interstices, about as broad as the ribs; the ribs project at the margin and make it conspicuously denticulate, they are slightly nodulous and waved and are covered, as well as the interstices, with radiating striae. Interior of shell smooth, slightly grooved by the ribs. Cup-shaped lamina much broken. Long. 9 mm, lat. 9,5 mm, alt. 3,5 mm.

I am not at all proud of this new species, as it is slightly defective, part of the outer shell and of the internal lamina wanting. Moreover I suppose it may be still rather young. As I failed to identify it with any of the known species, I asked the opinion of Mr. E. A. SMITH, who has at his disposal the types of the numerous species described by REEVE. The result was that Mr. SMITH declared it to be new. The most characteristic feature is the presence of comparatively strong ribs, conspicuously surpassing the margin of the shell. The dorsal view calls in mind some flat specimens of Amalthea conica Schum.

Indonesia. Sulawesi. Kwandang Bay.