Phylum Annelida and Its Classification | Coelomates | Zoology
The phylum Annelida contains segmented worms (such as the earthworm). The development of segmented bodies allowed the formation of specialised functions in different segments. Annelids have an enlarged coelom to accommodate more complex internal organs. The well-developed, fluid-filled coelom and the tough integument act as a hydrostatic skeleton. There are about 12,000 marine, freshwater, and terrestrial species usually divided into [...]