The juxta-ganglionic tissues of cephalopods consist of tubes containing columns of cells and nerve fibres. They arise in or near ganglia and pass to endings in the walls of veins or the organ of the anterior chamber of the eye. The latter is a system of vascular papillae presumably regulating the composition of the anterior chamber fluid. The strand of subpedunculate tissue, which joins the anterior chamber organ to the optic lobe, may provide a visual feedback for the regulation of intra-ocular pressure and the growth of the lens. The system is similar in those cephalopods whose anterior chamber is nearly closed (octopods, Sepia and Loligo ) and in those where it is widely open to the sea, Spirula and the oegopsids. In the stalk-eyed cranchiid Bathothauma the subpedunculate strand accompanies the optic tract to the brain and then returns along the stalk to the (open) anterior chamber. The sub-buccal tissue and neurovenous tissue of the vena cava resemble each other, and their fibres end on the walls of veins. They are well developed in Octopus and Eledone and especially so in the pelagic argonautids. They are less extensive in Sepia and Loligo . It is suggested that all the juxta-ganglionic tissues may be concerned with the regulation of the quantity and composition of body fluids by some modification of more usual nervous activities. The granules they contain suggest neurosecretion, but they may regulate by the operation of ionic pumps.