Colobocephalus M. Sars, 1870

The monotypic genus Colobocephalus was introduced by M. Sars (1870) for the species C. costellatus . It is characterised by a very thin and fragile internal auriform shell that possesses a short spire and prominent sutural lines. The aperture is wide, only outer lip present. The cephalic shield is rolled up anteriorly to form stumpy tentacles; eyes are visible. The foot is elongate, truncate and notched posteriorly, slightly lobed anteriorly. A median furrow on the sole is present. The animal is not able to retract into the shell completely. Operculum absent.