Shell hyaline, brownish, rarely white, biconical, with a clathrate sculpture made up of a dozen of strong axial costae, separated from each other by interspaces of about the same width than the axials, and crossed by thinner spiral cords; these spirals are darker in colour than the background. The species differs from the common granum by the spirals, which are much stronger in the latter, and less numerous; from strigilata by the thinner (and more widely spaced) radials of the tunisian species, which is also less slender.

Generic character: the protoconch « papillate of 1½ whorls, sculptured with granulose spiral threads, followed by an angulate whorl of closely spaced axials, crossed by two weak spiral cords. » – A. W. B. Powell: “The molluscan families Speightiidae and Turridae: an evaluation of the valid taxa, both recent and fossil, with lists of characteristic species”, Bulletin of the Auckland Institute and Museum num.5, nov. 1966, p.100.