174 
Proceedings of the Poyal Society of Edinburgh. [Sess. 
Diagram illustrating Oogenesis ( Early Maturation Phases). 
(^Oogonium (primordial germ cell). 
Capsular epithelial cell.(^) 
O 
Oogonium. 
Reserve cells. 
Primary oocyte.C^) 
Thin spireme. (^) 
Synapsis. (^) 
Thick spireme. Q 
Double filaments.^) 
Resting nucleus. (^) 
(^) Oogonium. 
(^Primary oocyte. 
6 6 
Reserve cells. Reserve cells. 
Conclusions. 
1. My observations show that the same plan of development is followed 
among varied types of the mammalian ovary, the variation depending on 
the rate of development ante- and post-natal, the cells maturing from the 
periphery inwards. 
2. The capsular epithelium is derived from the oogonia, and is differ- 
entiated at a very early stage, and has no function other than protective. 
3. I find that mitosis occurs among the oogonia, and also among the 
primary oocytes of the reticular stage. In this latter point I differ from v. 
Winiwarter. Mitosis ceases at a given stage in the development of the 
ovary. 
