Actinodiscidae with weak diffuse sphincter. Marginal tentacles small, delicate, apparently arranged in a single row but these communicating with the stronger endocoels a little longer than the others. Discal tentacles large, plump. simple, but, in the single known individual, usually appearing as large urn-like outgrowths. Between the marginal and discal tentacles a distinct, broad tentacle-free area.
O. torpida Duchassaing and Michelotti 1860
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1