After Parker, 1982

<==o Annelida Lamarck, 1809 [Clitellata] (annelid worms; nivelmadot)
   |-- Polychaeta Grube, 1850 [incl. Archiannelida] (polychaetes; monisukasmadot)
   `--+-- Oligochaeta (oligochaetes; harvasukasmadot)
      `-- Hirudinoidea (leeches; juotikkaat)

Reference(s):