| Longitudinal bands of muscle cells surrounding animal body, with one band running in each quadrant of the body, regulated contraction and relaxation of these muscles cause locomotion. | body wall musculature | body muscle | WBbt:0005813 | 
          
              | Complement of nervous tissue (neurones, nerves, receptors and support cells) serving to detect, relay and coordinate information about an animal`s internal and external environments and to initiate and integrate its effector responses and activities. | nervous system |  | WBbt:0005735 | 
          
              | neuron with its cell body situated in the head, excluding the pharynx. | head neuron |  | WBbt:0006751 | 
          
              | neuron with its cell body situated in the tail, posterior to rectum. | tail neuron |  | WBbt:0006759 | 
          
              | a group of hypodermal cells that lie along the apical midline of the hypodermis, at the extreme left and right sides between nose and tail | seam cell | lateral hypodermis | WBbt:0005753 |