1. The Golgi material of the oogonium and the early primary oocyte consists of spherical and rod-shaped bodies situated at one side of the nucleus. In older oocytes it is present as rods and granules distributed through the cell.
2. Granular mitochondria surround the nucleus of the oogonium and the early primary oocyte. In older oocytes they are scattered in groups through the cytoplasm. Later, they are arranged in a broad peripheral zone. In oocytes of Graafian follicles the majority of the mitochondria are situated in the central cytoplasm.
3. Small fat globules are present in young oocytes. In older oocytes the globules increase in size and number. There is a reduction in the size of the Golgi elements at the time when there is a marked increase in the amount of fat; this suggests that the Golgi material plays a part in the formation of the globules. Nucleolar material appears to be passed into the cytoplasm; it may contribute to the formation of nutritive material.
4. The position of the Golgi material of the follicle-cells suggests that the cells at first form a secretion which is passed into the oocyte, and later a secretion which enters the follicular cavity. Secretory granules are visible in many of the cells of late follicles. The position of the mitochondria appears to be correlated with the functional polarity of the cell.
1. The Golgi material of the spermatogonium, resting spermatocyte, and early spermatid consists of rods and granules situated at one side of the nucleus. The Golgi elements separate into two groups during nuclear division. Argentophilic and osmiophilic granules present at the posterior pole of the nucleus of the late spermatid probably originate from the Golgi material. The Golgi remnant is eliminated with the residual cytoplasm.
2. Accessory bodies are present in primary spermatocytes and in spermatids. An accessory body is present in the neck region of the spermatozoon.
3. The mitochondria are granular; their behaviour during spermatogenesis is described.
4. The formation of the acrosome and the nuclear-ring is briefly described.
5. The distal centriole passes undivided to the posterior end of the middlepiece. The manchette marks out the cytoplasm which is included in the middle-piece.
6. The protoplasmic bead, present at the anterior end of the middle-piece, is formed while the spermatozoon is within the testis.