Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801 Class Chondrichthyes Huxley, 1880 - cartilaginous fishes Subclass Elasmobranchii Bonaparte, 1838 - shark-like fishes see Infraclass Elasmobranchii Bonaparte, 1838 Order †Xenacanthida Glikman, 1964 see Order Xenacanthiformes Berg, 1955 1 Genus †Xenacanthus Beyrich, 1848