Shell white, shining, with from six to eleven whorls, which approach each other very closely, but touch only by the varical ribs, which number nine to eleven, slightly recurved, simple, slightly angulated above near the suture; aperture elliptic; base a little angular.
Length, 15 to 20; diameter, 6 to 8 mm.

Distribution: New York to Florida to Texas; Bermuda. Size: 18 to 25 mm .
Description: Color white; shape elongate-conic; sculpture with bladelike axial ridges forming angles on each shoulder that are stronger on earlier whorls, axial ridges fused with axial ridges from subsequent whorls; aperture subcircular; outer lip thickened and held away from body whorl by carina; anomphalous; operculum corneous. Habitat: In rubble or sandy bottoms, usually in association with sea anemones. Shells found at depths from 0 to 219 m (718 ft).
Remarks: Specimen in photograph from Port Isabel. See Clench and Turner (1951); Andrews (1977).

This species is found from Virginia south to Florida and west to Texas. Adults reach from 18-25mm. The angle of the costae, from which the shell derives is name, is quite variable. China white, 8 whorls, costae fused at contact, 9 to 12 costae. Chunkier than humphreysii and with a wider angle from the spire. A quite variable, but easily recognized species. Deep suture. Microscopic sculture, when present, visible only under high magnification. Slender specimens may be mistaken for E. humphreysii, a close relative.