[Phylum] Chordata Bateson, 1885 - chordates Subphylum Craniata auct. Infraphylum Vertebrata Lamarck, 1801 - vertebrates Superclass †Osteostracomorphi Class †Osteostraci Lankester, 1868 Order †Cephalaspidiformes Halstead Tarlo, 1967 Suborder †Ateleaspidoidei Family †Ateleaspididae Traquair, 1899, nom. praeval. Genus †Hemicyclaspis Lankester, 1870