[Kingdom] Animalia Linnaeus, 1758 - animals Grade Enterozoa Grade Cœlomata Phylum Appendiculata {Lankester} Branch Gnathopoda Straus-Durkheim, 1829 Grade Condylopoda Class Arachnida Lamarck, 1801 Branch Branchiopulmonata Order Xiphosura Latreille, 1802 see Class Xiphosura Latreille, 1802 Genus Limulus Müller, 1785