Souleyet, 1852
Shell very small (maximal diameter = 1.5 mm) and flat (body whorl flat-oval in cross section), with a high keel. Spire of about 4 and 1/2 whorls, bearing low spiral ridges that are highly variable, but generally more prominent than in animals from the Mediterranean Sea or the Indian Ocean (Richter, 1968, 1987). Pigmentation varies from colorless to faintly yellowish. Inner surface of shell at aperture may have a brownish hue. Eyes Type a. Radula relatively large, with monocuspid lateral teeth and strong sexual dimorphism (larger and broader, with large lateral and marginal teeth in males; more narrow and ribbon-like in females). This species has been confused with the following species in the past, but the differences between the two are clear (Richter, 1987).
See the family Atlantidae for a discussion of the species groups.