Shell very elongate-conic, light yellow. Nuclear whorls two, moderately well rounded, marked by six spiral threads, which are about as wide as the spaces that separate them, and numerous slender, closely spaced, axial threads, which are about one-fourth as strong as the spiral threads between which they occur, giving the entire surface a finely reticulated appearance. Post-nuclear whorls appressed at the summit, with a sloping shoulder which extends over the posterior fourth between the sutures, marked by strong, slightly retractive, axial ribs which are about one-fourth as wide as the spaces that separate them. Of these ribs, 14 occur upon the first, 16 upon the second, and 18 upon the penultimate turn. In addition to the axial ribs, the whorls are marked between the sutures by three strong, spiral cords which are almost as strong as the ribs and divide the spaces between the sutures into four almost equal portions. The intersections of the spiral cords and the axial ribs form strong tubercles, while the spaces inclosed between them are well impressed, rectangular pits, having then long axes parallel with the spiral sculpture. Suture strongly constricted. Periphery of the last whorl marked by a spiral sulcus equal to that which separates the supraperipheral spiral cord from its posterior neighbor and, like it, is crossed by the continuations of the axial ribs, wliich extend over the first two basal spiral cords and render them tuberculate. Base well rounded, rather short, produced anteriorly, marked by three strong, sublamellar, spiral cords which are about one-third as wide as the spaces that separate them. Aperture very oblique, twisted, ovate; posterior angle obtuse; outer lip thickened at the edge within the lip, reenforced behind the edge by a strong varix, inner lip very stout, strongly curved, and appressed to the base; parietal wall covered with a very thick callus, which renders the peritreme complete.
Professor Keep's cotypes were collected on mossy rocks at low tide at San Diego, California. One of these, the specimen figured, is Cat. No. 219564, U.S.N.M. This has 4 post-nuclear whorls and measures: Length 3.2 mm., diameter 1.8 mm.