ABSTRACT
The neurophysiological responses of an ophiuroid, recorded extracellularly from the radial nerve cord, to chemical, photic and Vibration stimuli are presented and discussed in relation to the behaviour of the whole animal in its natural environment. The responses to shadow and water movement in the aquatic medium are related to the detection of predators. An interoreceptor located within the arm spines is suggested as the receptor detecting water movement. Neurophysiological evidence of the ophiuroids ability to detect chemicals is presented, and the disadvantages of using behavioural changes to monitor the sensory discriminatory powers of echinoderms to perceive their environment are discussed.
