Kingdom Animalia Linnaeus, 1758 - animals Phylum Arthropoda Siebold, 1848 - arthropods Subphylum Cheliceriformes Class Chelicerata Heymons, 1901 Subclass Merostomata Dana, 1852 - horseshoe crabs see Class Xiphosura Latreille, 1802 1 Order †Eurypterida Burmeister, 1843 - eurypterids 2 Order Xiphosura Latreille, 1802 see Class Xiphosura Latreille, 1802