Thenaria (Endomyaria) with well developed base. Column smooth, its distal part somewhat folded. Sphincter very weak, restricted. Tentacles all of one sort, simple short, radially arranged over the endocoels as well as over the exocoels. Numerous perfect mesenteries.
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1