Originally published in Quaderni D'anatomia. Vol. III. Fogli della Royal Library di Windsor, Organi della Generazione, Embrione. C.L. Vangensten, A.M. Fonahn and H. Hopstock, editors. Christiania, J. Dybwad, 1913. ca. 1510-1512.Photo of the original from the Royal Library, Windsor. Originally drawn while Leonardo was an assistant to Marcantonio Della Torre, Professor of Anatomy at the Univrsity of Pavia. A ruminant (probably sheep or cow) pregnant uterus with its blood supply (top) and its "cotyledonary" placenta (bottom) with its blood supply.These images were taken while preparing a book (Wombs with a View, Springer, 2016) on the history of the illustrations and how they contributed to our understanding of anatomy and physiology of pregnancy, thereby enabling advances in the practice of obstetrics and gynecology.