In the head of the planarian there is a ganglion under the eyespots. They have two groups of nerve cell bodies, or cerebral ganglia, which is sometimes referred to as the organism's brain. From the ganglion, there are two nerve cords that extend to the end of the tail. From these two nerves running parallel of each other are nerves connecting to these cords at 90 degree angles, making the nerve system resemble a ladder.