The branchial gland: A site of haemocyanin synthesis in Octopus

Summary The paired branchial glands in cephalopods are essential for life. The electron microscope reveals them to consist of cells containing masses of endoplasmic reticulum organised in parallel arrays together with pale areas between the reticulum that contain vacuoles. All three regions of the cells contain masses of haemocyanin particles and it is suggested that the gland is the site of haemocyanin synthesis, the particles being made amongst the endoplasmic reticulum at discharged into the pale areas and vacuoles before being released into the general circulation.It is a pleasure to thank the Director and Staff of the Stazione Zoologica of Naples, and the Marine Biological Association Laboratory, Plymouth for their excellent facilities so freely provided. Much of the material was collected at Naples where one of us (JBM) was generously supported by the S.R.C. We thank many colleagues, too numerous to mention individually, who helped in different ways and we are grateful, too, for encouragement, support, and discussion, to Professors I. Chester Jones and J. Z. Young.