[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Vertebrata (Lamarck, 1801)
         Branch Craniata Linnaeus, 1758
           Grade Cyclostoma
             Class Hyperotreta
               1 Genus Myxine Linnaeus, 1758
               2 Genus Bdellostoma Müller, 1835 see Genus Eptatretus Cloquet, 1819