Small depressed cone-shaped shell with angular periphery, shallow suture, moderately wide umbilicus, and sculpture consisting of rounded tubercles becoming coarser with increasing whorls; upper-side sculpture with 3 main ribs (the uppermost somewhat stronger), sometimes with finer threads between them; angular prominent double keel formed by 2 main ribs (lower one somewhat weaker), and between them 1 strong additional rib flanked by finer threads; basal sculpture of 5-6 spiral ribs, innermost 2 with very coarse nodules; umbilical side of columellar wall frequently with 2 indistinct spiral projections. Whitish to light tan, spire darker, periphery lighter, usually with brown blotches; fresh specimens with 1 brown streak in aperture. Protoconch diameter 0.66-0.80 mm, distinctly heterostrophic, without anal keel.
Teleoconch: small, diameter of specimens in collections usually 5-8.5 at 3 1/8 - 3 7/8 whorls (rarely more than 4 whorls). Shape: depressed cone-shaped with angular periphery; moderately wide umbilicus (UD ca. 20% of SD); shallow suture. Sculpture: consisting of rounded tubercles, becoming coarser with increasing whorls; Upper side: SSR somewhat stronger than following single MR, sometimes with fine threads interspersed; Periphery: UPR almost identical to MR; large specimen usually with fine spiral thread between them; angular prominent double keel formed by LPR and somewhat weaker IPR; between them 1 relatively strong additional spiral rib, with 1 finer thread above (and in larger specimens also below) this rib; upper point of whorl attachment usually on or immediately below LPR; Base: 5-6 spiral ribs, increasing in width towards umbilicus; frequendy with additional finer threads interspersed; inner¬most 2 ribs (PUR and UC) with very coarse nodules, 8-11 on UC of body whorl; umbilical side of columellar wall convex, frequently with 2 indistinct spiral projections. Coloration: whitish to light tan, spire darker; periphery light, usually with ± regular brown blotches (usually only 1 nodule wide); UC lighter than basal area; parietal wall white; fresh specimens with 1 brown streak in the upper part of aperture. -Protoconch: small (0.66-0.80, x = 0.72), multispiral, distinctly heterostrophic, without anal keel; light tan. - Periostracum: thin, brownish. - Operculum: low cone-shaped, otherwise as described for subgenus. - Radula and Anatomy: not known. Lectotype: SD = 8.5, H = 5.6, PD = 0.7, Tw - 3 3/4+, UD = 1.1; holotype of H hedleyi: SD = 8.7, H = 5.9, PD = 0.68, Tw - 4 3/8, UD = 1.5.

Known from several localities in the Indian Ocean (Madagascar, Persian Gulf, India), from Indonesia and Queensland, Australia. Type localities: S. cerdaleum: "Persian Gulf, Fao, on telegraph-cable"; H. hedleyi: "Port Curtis, Queensland (23°52'S., 151°21'E.), 13-18 metres." Habitat: Sublittoral; available records from 7-31 m, live-collected type material from unrecorded depth ("on telegraph cable").