Annelida Lamarck, 1809 - segmented worms Class Oligochaeta Grube, 1850 - oligochaetes see [unranked] oligochaetous Clitellata Order Opisthopora 1 Family Glossoscolecidae Michaelsen, 1900 2 Family Megascolecidae Rosa, 1891 3 Family Moniligastridae 4 Family Ocnerodrilidae Beddard, 1891 5 Family Octochaetidae Michaelsen, 1900