The nervous system of the earthworm is basically represented by ganglia arranged segment wise on the ventral paired nerve cord. The nerve cord in the anterior region (3″‘ and 4’ segments) bifurcates, laterally encircling the pharynx and joins the cerebral ganglia dorsally to form a nerve ring. The cerebral ganglia along with other nerves in the ring integrate sensory input as well as command muscular responses of the body.
