Shell white, solid, rough, with six rapidly enlarging whorls; upper whorls rounded, last whorl with a tendency to applanation on the basal side; epidermis lost; spiral sculpture of (on the fourth whorl) live to (on the last whorl) twenty revolving ridges, which cross (on the fourth whorl) twelve to (on the last) ten varixlike ribs or costae extending completely around the whorl; these increase by dichotomy and between the costae are quite uniform, widening as they reach the crest of a varix and then suddenly diminishing in breadth to repeat the process at the next one ; between the spiral ridges the interspaces are channelled, and rarely contain a single a fine thread; beside the costal the whorls are crossed by beautifully fine and even raised line, corresponding in direction to the lines of growth, and only visible under a magnifier; aperture rounded, produced into the narrow canal in front; pillar with a thin lamellar callus (behind which is a narrow umbilical chink) and a slight toothlike projection on the inner side; interior of aperture shining, smooth. Lou. of shell, 9.25; of last whorl, 6.0; of aperture, 4.0. Lat. of shell, 6.0; of aper¬ture, 3.5 mm. Defl. 54°. Sigsbee, near Havana, 80 fms.
The first of the genus from tropical waters.