Thenaria (Endomyaria). Column smooth or provided with projections in the form of verrucae, marginal spherules, pseudospherules or vesicles which never have macrobasic amastigophors. Sphincter absent or endodermal diffuse to circumscribed. Tentacles simple, arranged in cycles. Never more than one tentacle communicating with each endo- and exocoel. Mesenteries not divisible into macro- and microcnemes. Perfect pairs of mesenteries rarely six, as a rule more than six.
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1
Electronic version made possible by NSF grant DEB95-21819 in the PEET program to D. G. Fautin.