Kingdom Protista (Haeckel, 1866) - protists
   Phylum Ciliophora Doflein, 1901 - ciliates
     Class Polyhymenophorea - spirotrichs see Class Spirotrichea Bütschli, 1889
       Subclass Spirotricha see Class Spirotrichea Bütschli, 1889
         Order Heterotrichida Stein, 1859 - heterotrichs
           Genus Blepharisma Perty, 1849
           Genus Spirostomum Ehrenberg, 1834
           Genus Stentor Oken, 1815