Family TETRAHYMENIDAE Corliss, 1952

Syns.

Deltopylidae, Frontoniidae p.p., Leucophry[i]dae

With general characteristics of suborder s.s. (above); body pyriform to elongate-ovoid to cylindrical in shape; membranellar bases of uniform width; one to three (up to nine in Lambornella) postoral kineties, rightmost one typically stomatogenic; some species with caudal cilium; members of one genus (Tetrahymena) unique in exhibiting polymorphism (microstome-macrostome stages, cysts, etc.) and (endo)symbiosis in variety of hosts (slugs, snails, clams, enchytraeid worms, midges, mosquitoes, tadpoles, fishes, etc.); fresh-water or edaphic habitats.

Colpidium Stein, 1860 (syn. Dexiostoma). Several species.
Deltopylum Fauré-Fremiet & Mugard, 1946. Single species.
Lambornella Keilin, 1921 (resurrected genus). Few species.
Stegochilum Schewiakoff, 1893. Few species.
Tetrahymena Furgason, 1940 [a nomen conservandum; principal syns. Leptoglena, Leucophryclium, Leucophrys, Paraglaucoma (of Kahl and of Warren [hom.] ), Protobalantidium, Roquea, Tetrahymen, Tetrahymenia, Turchiniella] . Many species.
Incertae sedis:
Blepharostorrea Schewiakoff, 1893, single species;
Malacophrys Kahl, 1926, few spp.