Rights: University of Waikato Published 17 September 2009 Download



They don't have a central nervous system. They have something called a nerve net, which is basically just all their nerves are spread over their whole body. But they can still move in a co-ordinated directional manner. So they’ll have parts of their body which are detecting a stimulus, and they’ll move towards that or move away from it if it’s something they want to go to or something that’s annoying them.