Teleoconch: shell very small to large (usually 8-30 mm), depressed cone-shaped with sharp peripheral keel and very wide umbilicus (ca. 40% of shell diameter); whorls in larger specimens bulging, concave on either side of the peripheral keel; distinct axial growth marks on entire shell surface; upper (apical) side with four distinct, nodose spiral ribs and often finer threads between them, followed by a peripheral region of two stronger spiral ribs (UPR and LPR) with several interspersed threads; this peripheral area variously formed, in Recent species as part of the apical sculpture under formation of a concave area, with the LPR forming the peripheral keel; upper point of whorl attachment at peripheral keel; nodules of keel often produced into numerous narrow spines or few flattened teeth; base bulging, with numerous fine spiral ribs, increasing in width towards the umbilicus (larger specimens with finer threads between them); innermost basal rib (UC) deeply sunken into umbilicus, often appearing as sculpture of umbilical wall; area between UC and usually stronger proxumbical rib in Recent species at oblique angle to base; umbilical wall with growth lines, occasionally with very fine spiral sculpture; coloration: off-white or irregularly blotched yellowish tan. Protoconch: small to medium-sized (ca. 0.7-1.2), distinctly heterostrophic, without anal keel. Radula: cuticularized, large rod-like structure instead of true radula (asperum, others unknown). Operculum: horny, round, cone-shaped, with peg-like projection on body side.