Fauré-Fremiet in Corliss, 1956
Paroral membrane often prominent, infraciliary base tripartite: short "a", elongate "b" and "c" segment as permanent scutica. Cytostome equatorial or subequatorial. Caudal cilia conspicuous in many species. Rarely with director meridian. Two types of mucocysts. Body typically small to very small with occasional exceptions. Widely distributed, free-living marine species; some commensal in molluscs; some in freshwater or edaphic habitats, few coprozoic.
Family Pleuronematidae
Family Cyclidiidae