[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlentera
       Phylum Nematophora Huxley, 1850
         Class Hydromedusæ see Class Hydrozoa Owen, 1843
           1 Order Hydriformes
           2 Order Siphonophora Eschscholtz, 1829 - siphonophorans
           3 Order Monopsea