[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Appendiculata {Lankester}
         Branch Chætopoda
           I Class Oligochæta Grube, 1850 - oligochaetes see [unranked] oligochaetous Clitellata
           II Class Polychœta
           Appendix a Order Myzostoma
           Appendix b Order Archisyllidea