Actinernidae with cylindrical body not lobed above. Ectoderm of the column with small nematocyst batteries. No sphincter. Tentacles up to over 100 arranged about as in Halcurias. Longitudinal muscles of tentacles ectodermal, rather weak, radial muscles of oral disc strong, meso-ectodermal, 2 siphonoglyphs. Mesenteries numerous, all perfect in older specimens, their arrangement cyclic but not very regular, the two partners of a pair generally about equally developed. Longitudinal muscles of mesenteries and parietobasilar muscles weak. No basilar muscles. Cnidom: see the suborder.
Ilyanthopsis elegans Wasilieff [sic] 1908
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1