The general histology of the ovary and the cellular morphology of oöcytes in Henricia sanguinolenta (Muller) Bell is described.
The single nucleolus in the germinal vesicle begins to multiply when the oöcyte is 90 μm in diameter, either by fragmentation or by budding and it reaches several hundred in number in a full grown oöcyte of 1200 μm in diameter. At no time during the oöcyte growth is RNA synthesis in the nucleolus or any other parts of the oöcyte detected by autoradiographic techniques. However, follicle cells and coelomocytes in the ovary are actively synthesizing RNA during this period.
The inactivity of RNA synthesis in oöcytes is discussed.