Protozoa Goldfuss, 1818 - protozoans Phylum Ciliophora Doflein, 1901 - ciliates Class Oligohymenophorea de Puytorac et al., 1974 - oligohymenophoreans Subclass Hymenostomatia (Delage & Hérouard, 1896) Cavalier-Smith, 1993 - hymenostome ciliates Order Astomatida Schewiakoff, 1896