Phylum Chordata Bateson, 1885 - chordates Subphylum Vertebrata Cuvier, 1812 - vertebrates Superclass Agnatha Haeckel, 1895 see Class Agnatha Cope, 1889 Class Monorhina Haeckel, 1895 see Class Cephalaspidomorphi Moy-Thomas & Mile, 1971 Subclass Hyperoartii see Order Petromyzontiformes Berg, 1940 Superorder Petromyzonida