<P> In the male the Müllerian ducts atrophy, but traces of their anterior ends are represented by the appendices testis (hydatids of Morgagni of the male), while their terminal fused portions form the utriculus in the floor of the prostatic urethra . This is due to the production of Anti-Müllerian hormone by the Sertoli cells of the testes . </P> <P> In the female the Müllerian ducts persist and undergo further development . The portions which lie in the genital cord fuse to form the uterus and vagina . This fusion of the Müllerian ducts begins in the third month, and the septum formed by their fused medial walls disappears from below upward . </P> <P> The parts outside this cord remain separate, and each forms the corresponding Fallopian tube . The ostium of the fallopian tube remains from the anterior extremity of the original tubular invagination from the abdominal cavity . </P> <P> About the fifth month a ring - like constriction marks the position of the cervix of the uterus, and after the sixth month the walls of the uterus begin to thicken . For a time the vagina is represented by a solid rod of epithelial cells . A ring - like outgrowth of this epithelium occurs at the lower end of the uterus and marks the future vaginal fornix . At about the fifth or sixth month the lumen of the vagina is produced by the breaking down of the central cells of the epithelium . The hymen represents the remains of the Müllerian eminence . </P>

Where does the foetus develop in the female reproductive system