Shell somewhat variable, small, white, the first six whorls rather slender, giving a subcylindrical appearance, the latter whorls, if any, enlarging more rapidly ; whorls about eight, of which about two are nuclear ; nucleus large, white, smooth, unsculptured, forming for the shell a rather blunt button-like apex ; succeeding whorls marked by a transverse sculpture of twelve to (on the last turn) eighteen narrow, oblique, flexuous ribs, which begin as little sharp nodules at the suture, are evanescent over the notch-band, thence continue to the next suture, or in the last whorl become evanescent at its anterior third; these ribs are crossed by a variable number of rather sharp revolving threads, with wider interspaces, usually three or four in number (on the older whorls) to sixteen (on the last whorl), beginning just in advance of the band ; the first two are most prominent, and angulate the riblets where they cross them, producing little raised points; the succeeding threads are a little enlarged where they cross the ribs, but do not form points, and are as usual closer together on the anterior part of the canal; on the band is no sculpture except the lines of growth and an occasional faint indication of revolving striae ; the number of riblets and of threads with their respective sharpness and the prominence of the nodules are somewhat variable; the band is somewhat excavated, tending to give a turreted appearance in old shells; notch broad, not deep ; outer lip thin, produced forward ; pillar straight, anteriorly attenuated, with very little callus ; lines of growth well marked all over the shell. Lon. of shell, 9.0 ; of last whorl, 5.0; of aperture, 3.75. Max. lat. of shell, 2.5 to 3.0 ; of aperture, 1.0 mm. Defl. 24° to 27°.

Off Havana. Yucatan Street.