170 Proceedings of the Royal Society of Edinburgh. [Sess. 
figured by v. Winiwarter and Sainmont. The cells with double filaments 
have a large amount of cytoplasm and a distinct cell membrane, which lies 
in contact with the follicle cells. Reserve cells are numerous near the 
early follicles. In the human foetal ovary the cells are mixed up, and later 
stages of cells may be found near the periphery, while early stages are 
found near the central portion. The cells at the periphery are dense in 
appearance. The chromatin filaments are thicker than in other types, 
their distribution being easily made out in the nucleus. Syncytial masses 
are not so evident, and the cell membranes are well defined. Cells in mitosis 
are numerous in the peripheral layers. Irregular rows of cells in the hilum 
may be the remains of medullary cord formation (fig. 19). Nuclei con- 
taining short rods of chromatin are numerous, these being filaments cut 
in transverse section. 
Fifth-month Foetus. — The volume of the ovary is greater, the cortical 
zone is thicker, and the stroma dense and nearer the periphery. Mitotic 
figures are not so marked. Cells in synapsis are numerous, and those cells 
in the deeper layers show double filaments. 
Sixth-month Foetus. — The ovary is somewhat trilobed, with deep furrows 
on its surface. The differentiation between cortex and medulla is not well 
marked. The stroma cells are nearer the periphery. Cells of the first- 
stage oocyte are scanty and near the surface. In the deeper layers are 
synaptic, thick spireme and double filament stages. Follicles are more 
numerous, and contain a single row of follicle cells. Reserve cells are not 
so numerous. 
Seven to seven-and-a-half months Foetus. — The ovary is more flattened 
in appearance, with a distinct trilobed outline. The medulla is narrow. 
The capsular epithelium is isolated in places by the stroma cells. Follicles 
are seen all over the cortex, with oogonia in between. Reserve cells are not 
numerous. No oocytes of the first stage are seen. A few in synapsis and 
thick spireme are found, but the majority of the cells are in the double 
filament stage and surrounded with follicle cells. In some follicles the 
axes of the cells are perpendicular to the oocyte cell membrane, in others 
they are parallel to it. In the deeper cortical layers are several rows of 
follicle cells. 
New-born. — The volume is greater and flattened antero-posteriorly. 
The stroma cells form a band under the capsular epithelium, whose nuclei 
are cubical in shape, their axes lying parallel or obliquely to the underlying 
cells. The oocytes are in the double-filament stage, those cells containing 
a large amount of deutoplasm which is granular and vacuolated in places. 
Some of the follicles contain two oocytes (fig. 20). The beaded appearance 
