Neurosecretion in the Ophiuroid Ophiopholis aculeata.

Neurocrine activity has been demonstrated for the first time in the Ophiuroidea and for only the second time in the phylum Echinodermata. Three types of neurosecretory cells have been shown, by means of histological staining techniques, to occur in the principal motor ganglia. The secretory products are carried away from the cell bodies by axon transport but cannot be traced to special terminal reservoirs. It is possible that the neurosecretory products diffuse into adjacent coelomic spaces for further transport. It is suggested that in the echinoderms neurocrine secretions may be associated with control functions which in other phyla are regulated by. endocrine products.