Subclass (2) Peritricha Stein, 1859

Syns.

Cyclohymenophora, Dexiotricha, Peritrichasina, Peritrichia, Peritrichidea, Peritrichorida, Stomatoda

Body characteristically inverted bell- or goblet-shaped or conical-cylindrical; conspicuous buccal ciliature, winding counterclockwise, at apical pole and a scopula (plus prominent holdfast derivatives: usually contractile stalk or complex adhesive disc) at antapical pole; somatic ciliature reduced to subequatorial locomotor fringe (trochal band); a ciliated infundibulum into which the contractile vacuole empties, leads to the cytostome; stomatogenesis buccokinetal, with plane of fission of body parallel to major axis; dimorphism (with migratory telotroch stage), colonies, loricae or thecae, and cysts common in the life cycle of many species; conjugation ("total") invariably involves fusion of a micro- with a macroconjugant; very widespread aquatic distribution, with species generally free-living or occurring as symphorionts on diverse hosts, but with some as commensals or even parasites on or in other organisms (ranging from protozoa to vertebrates).

Order PERITRICHIDA Stein, 1859