Thenaria (Acontiaria) whose acontia are provided with microbasic b-mastigophors and microbasic amastigophors, the latter sometimes very rare or absent in the adult. Sphincter mesogloeal. Mesenteries not divisible into macro- and microcnemes.
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1