Phylum Annelida

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)