Coordination of Juxtaposed Muscle Layers as Seen in Hydra

Abstract

Fish guts, rabbit oviducts, worms, blood vessels and Hydra share with each other the problem of coordinating juxtaposed layers of muscle. In Hydra, as in the viscera of vertebrates, there is now compelling evidence that this coordination is essentially mediated by nerves acting on sheets of electrically conducting muscle cells. In fact, the best way to look at Hydra, is probably to see it as a miniature vertebrate gut with nematocysts and tentacles. Looking at it in this way immediately causes much of its behavioral system to fall into place.