The NErvous System of Persian carpet flatworms
These flatworms have touch-sensing cells on their sides in the form of cilia. They have "ocelli" which means "little eyes" in Latin. They tell the animal in which direction light is coming at them, so that they can avoid it, as they thrive in the dark. There is a large concentration of nervous tissues in the head area of the flatworm, which take the form of a brain, which has one to four nerve cords which run throughout the body.