Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Metazoa Haeckel, 1874 see Kingdom Animalia Linnaeus, 1758
     Division Eumetazoa Butschli, 1910 see Subkingdom Eumetazoa Butschli, 1910
       Subdivision Bilateralia
         Phylum Platy-helminthes see Phylum Platyhelminthes Gegenbaur, 1859
           Class Turbellaria Ehrenberg, 1831 - planarians see Subphylum Turbellaria Ehrenberg, 1831
             Superorder Neoophora see Class Neoophora
               Order Seriata
                 Suborder Tricladida Lang, 1884 see Order Tricladida Lang, 1884
                   Paludicola Hallez, 1892
                     Genus Polycelis Ehrenberg, 1831
                       1 Polycelis cornuta (Johnston, 1822)
                       2 Polycelis nigra (Müller, 1773)