Eukaryota Chatton, 1925 - eukaryotes see Domain Eukaryota Chatton, 1925
   Opisthokonta Cavalier-Smith, 1987 - opisthokonts see Clade Opisthokonta Cavalier-Smith 1987, nom. cl. inval.
     Metazoa Haeckel 1874 - multicellular animals see Kingdom Animalia Linnaeus, 1758
       Eumetazoa Bütschli, 1910 - eumetazoans
         Phylum Cnidaria Hatschek, 1888 - cnidarians
           Medusozoa Petersen, 1979 see Subphylum Medusozoa Petersen, 1979
             Class Hydrozoa Owen, 1843
               A-Forms
                 Order Siphonophora Eschscholtz, 1829 - siphonophorans
                   1 Suborder Cystonectida
                   2 Suborder Physonectida - physonects
                   3 Suborder Calycophorida - calycophores