Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Protozoa Goldfuss, 1818 see Kingdom Protozoa Goldfuss, 1818
     Class Ciliata see [unranked] ciliates
       Order Spirotricha
         Suborder Heterotricha Stein, 1859
           Genus [Balantidium] Claparède & Lachmann, 1858
             1 Balantidium coli (Malmsten, 1857) Stein, 1863