[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 Trilobitina
                   1 Genus Phacops Emmrich, 1839
                   2 Genus Ilenus Rafinesque, 1832, nom. null. see Genus Illaenus Dalman, 1827