[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlentera
       Phylum Nematophora Huxley, 1850
         Class Hydromedusæ see Class Hydrozoa Owen, 1843
           Order Monopsea
             1 Genus Geryonia Péron & Lesueur, 1810
             2 Genus Æginopsis Brandt, 1835