Also known as the ringed worms or segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches.
It contains over 11,000 species of aquatic animals (including corals, jellyfish, sea anemones, hydra) found both in freshwater and marine environments, though predominantly marine.
They include starfish, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies, making a total of about 7000 species.
of relatively simple bilaterian, unsegmented, soft-bodied invertebrates with no body cavities.