Fishes Class Myxini Jaekel, 1911 Order Myxiniformes - hagfishes Family Myxinidae Rafinesque, 1815 - hagfishes Subfamily Eptatretinae Bonaparte, 1850 - multi-gill hagfishes Genus Heptatremus Swainson, 1839, nom. null. see Genus Heptatrema Duméril, 1832, nom. van.