« Shell sinistral with higher or lower spire, no umbilicus, but columella twisted, forming basal rostrum with membrane in most species; last whorl relatively large; subsutural crests and/or spines on apertural margin present in some species, epidermis with reticulate pattern (cuticulum). Epi- to mesopelagic, some species bathypelagic. » – Janssen, Bush & Bednaršek: “The shelled pteropods of the northeast Pacific Ocean (Mollusca: Heterobranchia, Pteropoda)”, Zoosymposia vol. 13, 2019, p.336. The family has only one genus.
 

The description of the genus, given by Forbes, is rather short: « …small reversed, spiral shells, having the aperture more or less prolonged into a pointed canal. » – E. Forbes: “Report on the Mollusca and Radiata of the Aegean sea, and on their distribution, considered as bearing on geology”, Reports of the British Association for the Advancement of Science for 1843, London 1844, p. 186.