[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Platyelmia
         Branch Suctoria
           Class Hirudinea Lamarck, 1818 - leeches see Subclass Hirudinida
             1 Order Pericœla
             2 Order Bdellidea