The brain is small and is located near the pharynx. A ventral nerve cord extends from the brain and runs the length of the body. In each segment it swells to form a structure called a ganglion. The nitrogenous waste is removed from the body by structures called nephridia. Each segment contains 2 nephridia except the first 3 and the last one.
Earthworms are hermaphroditic.
They contain both male and female reproductive organs in the same body. These animal usually cannot fertilize themselves. Their fertilized eggs develop into trochophore larvae. These larvae are also found in the phylum Mollusca. Their muscular system contains both circular and longitudinal muscles.