Rather large (43-120 mm), elegant shell with 11-13 strongly convex whorls with constricted suture. Shell withish, sometimes dirty grey in colour.
All whorls with prominent rounded axial ribs, increasing numerically but decreasing in strength anteriorly. Upper whorls with 6-7 ribs, lower whorls with up to 16 ribs, body whorl often without ribs.
Upper whorls crossed by 6-8 prominent spiral cords, body whorl with about 9-12 spirals, sometimes with weaker threads between them.
Aperture ovate, parietal callus extended, forming a sharp, thin lamina along the columellar border of aperture. With simple, usually paired lirae within aperture. Siphonal canal slender and long, sculptured with strong spiral cords of unequal strength.

F. stegeri is distinguished from the similar F. excavatus by its larger size, possession of narrower and more numerous axial ribs on latter whorls, and by its entirely white colouration.
F. halistreptus has only very low, rudimentary ribs and occurs at greater

Range: West coast of Florida, Eastern Gulf of Mexico.