Main Characteristics

  • Elongated, segmented, coelomate (true body cavity) worm-like animals.
  • Body provided with setae or parapodia for locomotion.
  • Well developed digestive system with the alimentary canal open at both the ends.
  • Excretory organs called nephridia.
  • Sexes united (as in earthworm) or separate (as in Nereis).
  • Regeneration quite frequent.
  • Aquatic, some terrestrial animals, some living in tubes and some even parasitic.

Examples: Nereis, Earthworms like Pheretima (free-living in soil), Hirudinaria (leech, a parasitic on cattle)