The nervous system of the ephyra larva of Aurellia aurita

Summary The rapid co-ordination of the beat had been identified with a specialized system of neurones which spreads over the muscles from the marginal ganglia. By analogy with other invertebrates this has been called the giant fibre system. The feeding response and the spasm are co-ordinated by a separate net, called ‘the diffuse nerve-net’, which is both physiologically and histologically distinct from the giant fibre system. The histological structures of the two nerve-nets and the marginal ganglia are described. Although the diffuse nerve-net contains sensory cells, it also acts upon the muscles, and a double motor innervation is indicated. The two nerve-nets meet and interact at the marginal ganglia. An attempt has been made to interpret the neurone structure of the ganglia.