Phylum Annelida
The annelid phylum contains about 9,000 documented species of worms that traverse both land and sea. Annelids include species like leeches, marine worms, and earthworms. Though it is often dismissed, much of human livelihood is dependent on annelids like earthworms. This is because earthworms are responsible for keeping the soil that humans farm fertile. Much like anthropods, annelids are also segmented organisms. Annelids usually possess both circular and longitudinal muscles, have a digestive system made up of a mouth, gut, and anus that runs the length of their body, and have a closed circulatory system.