Co-Ordinating Systems and Behaviour in <i>Hydra</i>

Abstract

ABSTRACT In the first paper of this series (Passano &amp; McCullough, 1964) we described the system concerned with the periodic bursts of impulses arising from the subhypostome and conducted throughout the column of several species of the genus Hydra, the familiar freshwater polyp (hydrozoan coelenterate). Each of these bursts of impulses is followed by a co-ordinated contraction of the epidermal, longitudinally arranged muscles, so that the total burst of this contraction-burst system results, in reducing the animal to a stubby ball. Periodic contraction bursts (CB) are the most important overt behaviour of Hydra.