In a recent article I stated that I 1 believed that perforating hemorrhagic (chocolate) cysts of the ovary were hematomas of endometrial type, and that at the time of the perforation of the cyst some of the epithelium lining it might be carried with the contents of the cyst into the peritoneal cavity. This epithelium might become lodged on the surface of the peritoneum, soiled by the contents of the cyst, and there develop into adenomas of endometrial type. The adenomas arising from the implantation of this epithelium might be small and quiescent, or they might become invasive, giving rise to so-called adenomyomas of the part invaded. I compared the conditions arising from the perforation of these cysts with the implantations of ovarian papilloma and cancer resulting from the rupture or perforation of an ovarian tumor containing these growths. These cysts were described as developing most frequently in women between