Protozoa Goldfuss, 1818 - protozoans Phylum Ciliophora Doflein, 1901 - ciliates Class Polyhymenophorea - spirotrichs see Class Spirotrichea Bütschli, 1889 Subclass Spirotrichia Order Oligotrichida Bütschli, 1889 see Subclass Oligotrichia Bütschli, 1889