Histological and histochemical observations of the cephalic neurosecretory system of the crab, Paragrapsus Gaimardii (H. Milne Edwards)

Anatomical, cytological and histochemical features of the neurosecretory system of the crab, Paragrapsus gaimardii are described, In the brain and the commissural ganglia, three types of neurosecretory cells are distinguished, The distribution of these cells in the brain and the commissural ganglia is described. In the eyestalk, four types of neurosecretory cells are identified and the distribution of these cells is described. The neurosecretory cells of the brain, the commissural ganglia, and of the eyes talks are all paraJdehyde fuchsin - positive (PFpositive), Their tinctorial properties with the chrome, haematoxylin phloxine technique are described. The neurohaemaJ organ of the eyestalk, the sinus gland, is described both as regards its anatomical characters and its staining properties. The presence of allochthonous cells in the sinus gland is revealed, The allochthonous neuroglial cells of the sinus gland do not appear to be active gliosecretory cells, However, some of the neuroglial cells of the brain, especially those of the protocerebrum, do appear to be active gliosecretory cells. The neurosecretory material of the cephalic neurosecretory system of P. gaimardii is proteinaceous with disulphide groups being markedly present