AbstractHypophysectomy inO. punctatusresults in the atrophy of gonads and low activity of thyroid gland. The pituitary gland does not exert its influence on immature ova, but has decisive control over mature and maturing ova as well as over the germ cells in the testis. Changes in thyroid follicles in the absence of the pituitary gland are reduction in number, flattened epithelial cells, and accumulation of colloid in the follicles.