Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Metazoa Haeckel, 1874 see Kingdom Animalia Linnaeus, 1758
     Division Eumetazoa Butschli, 1910 see Subkingdom Eumetazoa Butschli, 1910
       Subdivision Coelenterata Hatschek, 1888 see Infrakingdom Coelenterata Leuckart, 1847
         Phylum Cnidaria Hatschek, 1888 - cnidarians
           Class Hydrozoa Owen, 1843
             01 Order Athecata see Order Anthoathecatae
             02 Order Lymnohydrina
             03 Order Hydrina
             04 Order Halammohydrina
             05 Order Siphonophora Eschscholtz, 1829 - siphonophorans
             06 Order Thecaphora
             07 Order Trachymedusae Haeckel, 1866 see Suborder Trachymedusae Haeckel, 1866
             08 Order Narcomedusae Haeckel, 1879 see Suborder Narcomedusae Haeckel, 1879
             09 Order †Stromatoporoidea Nicholson & Murie, 1878 see Class Stromatoporoidea Nicholson & Murie, 1878
             10 Order †Sphaeractinoidea Kühn, 1927