Phylum Annelida Lamarck, 1809 - segmented worms 1 Class Polychaeta Grube, 1850 - polychaetes 2 Class Oligochaeta Grube, 1850 - oligochaetes see [unranked] oligochaetous Clitellata 3 Class Hirudinea Lamarck, 1818 - leeches see Subclass Hirudinida