After an historical introduction, in the course of which the author gave an abstract of the important observations of Pflüger and Waldeyer, he proceeded to state his own observations on the development of the ova and structure of the ovary in calves, kittens, and the human female. The following general conclusions have been arrived at by the author in the course of his investigations :—

The corpuscles of the germ epithelium are derived by direct proliferation from those columnar corpuscles which invest the median side or surface of the Wolffian body, and which are continuous with the layer of columnar corpuscles that lines the pleuro-peritoneal cavity of the embryo in the early stages of development. The stroma of the ovary in the early stages of development is produced by a direct growth out from the interstitial tissue of the Wolffian body immediately beneath the germ epithelium on the median side of the Wolffian body.