Shells minute to small, varying considerably in morphology, from the limpet-shaped Amathina to the acteon-like Leucotina.
 

« uborbicular; spire small, depressed, or but little prominent; shell costate, ribs revolving, distant, prominent; last whorl flattened above; umbilicus small, and the space beneath it channelled; peristome continuous. » – T. A. Conrad: “Descriptions of new genera, subgenera and species of Tertiary and Recent shells”, Proceedings of the Academy of Natural Sciences vol.14, Philadelphia 1862, p.288. The original description of the synonym Carinorbis is, as for it, anatomical: « Animal bearing a marginally crenellated mantle; no velum between the tentacles » – M. C. Récluz: “Observations sur le genre Fossar (Fossarus)”, Journal de conchyliologie vol.12, Paris 1864, p.251. Shell capuliform, more or less globose, umbilicate, always radially sculptured, heavily spirally corded except in naticoides Dall, with a large body whorl; no siphonal notches in the aperture; columella smooth.