Three zones become recognizable in the cortical layer, one after the other. The outermost zone contains proliferating oogonia. Further in, there are oocytes undergoing the prophase of meiosis. From month 5, a third zone arises still further in. This zone features oocytes which have completed the prophase of meiosis and become surrounded by flat, epithelium-like cells, called the follicular cells. Through these means, primordial follicles develop. At around month 6, the whole cortical layer becomes uniformly filled with primordial follicles. The ovarian rete has no contact with the mesonephros nor the mesonephric duct.