Superphylum Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
   Phylum Chordata Bateson, 1885 - chordates
     Subphylum Craniata auct. see Subphylum Vertebrata Cuvier, 1812
       Superclass Myxinomorphi [monotypic]
         Class Myxini (Jaekel, 1911) [monotypic] see Subclass Myxinoidea
           Order Myxiniformes - hagfishes
             Family Myxinidae Rafinesque, 1815 - hagfishes
               Subfamily Eptatretinae
                 1 Genus Eptatretus Cloquet, 1819
                 2.1 Genus Paramyxine Dean, 1904 see Genus Eptatretus Cloquet, 1819
                 2.2 Genus Quadratus Wisner, 1999 see Genus Eptatretus Cloquet, 1819