Thenaria (Endomyaria) with well developed base. Column with more or less distinct verrucae in its upper part. Sphincter weak, restricted or circumscribed. Oral disc sometimes thrown into numerous short, cyclically arranged, permanent lobes; or sometimes not. The lobes, when present, bear on the oral side dendritic tentacles which are continued on the disc and radially arranged, on the aboral side a group of nematospheres. At the margin a cycle of dendritic exocoelic tentacles. Longitudinal muscles of tentacles absent or very weak. 2 siphonoglyphs or several, the latter not connected with directives. Pairs of mesenteries numerous, many perfect, directives present or absent. Retractors well developed, diffuse, band-like. Parietobasilar muscles weak, basilar muscles well developed. Distribution of gonads varying, the mesenteries of the first cycle, apart from the directives, may be fertile. Cnidom: spirocysts, basitrichs, microbasic p-mastigophors.
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1