Thenaria (Endomyaria) the column of which is usually divisible into scapus and scapulus. Marginal pseudospherules sometimes present. Sphincter absent, diffuse or circumscribed. Tentacles few. Longitudinal muscles of tentacles and radial muscles of oral disc ectodermal or mesogloeal. 2 siphonoglyphs. Mesenteries divisible into macro- and microcnemes, the latter often present only in the lowermost part of rhe [sic] body. Macrocnemes often 6 pairs with strong retractors, which may be circumscribed or strongly restricted. Parietobasilar muscles often very strong. Basilar muscles distinct.
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.