Order Sessilida Kahl, 1933

Fam. Astylozoidae Kahl, 1935
Fam. Ellobiophryidae Chatton & Lwoff, 1923
Fam. Epistylididae Kahl, 1933
Fam. Lagenophryidae Bütschli, 1889
Fam. Operculariidae Fauré-Fremiet in Corliss, 1979
Fam. Ophrydiidae Ehrenberg, 1838
Fam. Opisthonectidae Foissner, 1976
Fam. Rovinjellidae Mathes, 1972
Fam. Scyphidiidae Kahl, 1933
Fam. Termitophryidae Lom in Corliss, 1979
Fam. Usconophryidae Clamp, 1991
Fam. Vaginicolidae de Fromentel, 1874
Fam. Vorticellidae Ehrenberg, 1838
Fam. Zoothamniidae Sommer, 1951