Annelids are creatures with segmented bodies and simple nervous systems. Many small invertebrates such as earthworms and leeches fall under this phylum. Many annelids are used as bait during fishing (ie earthworms and Polychaetes). The nervous systems of these animals center around connecting the various segments of the body so that movement can occur. Many annelids posses the ability to regenerate after being wounded, such as leeches and earthworms.