NEUROSECRETION. X. A RELATIONSHIP BETWEEN THE PARAPHYSIS AND THE PARAVENTRICULAR NUCLEUS IN THE GARTER SNAKE (THAMNOPHIS SP.)

¹ Department of Anatomy, University of Colorado School of Medicine, Denver, Colorado

In snakes, as in other vertebrates, the neurosecretory cells of the supraoptic and paraventricular nuclei discharge their products by way of their axons into the pars nervosa of the pituitary gland. In the garter snake (Thamnophis sp.) another, hitherto undescribed neurosecretory pathway exists: secretory granules can be traced along processes of cells of the paraventricular nuclei to the commissura pallii posterior and the paraphysis. The granules accumulate in the commissura pallii posterior in a manner similar to that observed in the stalk of the pituitary.