Eukaryota Chatton, 1925 - eukaryotes see Domain Eukaryota Chatton, 1925
   Phylum Alveolata Cavalier-Smith, 1991 see Superphylum Alveolata Cavalier-Smith, 1991
     Subphylum Ciliophora Doflein, 1901 see Phylum Ciliophora Doflein, 1901
       Class Spirotrichea Bütschli, 1889
         1 Subclass Heterotrichia (Stein, 1859) Cavalier-Smith, 1993
         2 Subclass Oligotrichia Bütschli, 1889
         3 Subclass Stichotrichia Small & Lynn, 1985
         4 Subclass Hypotrichia (Stein, 1859) Cavalier-Smith, 1993