
IN MAN AND OTHER MAMMALIA. Ar 
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. 
The germ epithelial corpuscles proliferate by fission. In the human fecetal 
ovary of 74 months they measure z;5oth to gopoth of an inch in their longest 
diameter, and about 3,/55th of an inch in their shortest diameter. Each germ 
epithelial corpuscle is a nucleus surrounded by a thin film or investment of clear 
protoplasm. In the act of becoming primordial ova, the nucleus of each germ 
epithelial corpuscle swells up into a spherical body, within which is generally 
seen a nucleolus, and around which is produced clear homogeneous protoplasm 
which subsequently forms the yelk of the ovum. Germ epithelial corpuscles 
are seen on the surface of the ovary in all stages of development into primordial 
ova. In each primordial ovum the spherical germinal vesicle presents a sharply 
defined limiting membranous wall. Within the germinal vesicle is the nucleolus 
or germinal spot. All the ova in the ovary are derived from germ epithelial 
corpuscles. 
In all parts of the germ epithelium processes of vascular connective tissue 
stroma grow in between and around certain of the germ epithelial corpuscles, 
whereby the latter become more and more imbedded in the stroma of the ovary. 
Germ epithelial corpuscles are being constantly produced on the surface of the 
ovary, to take the place of those already imbedded in the stroma. The imbedded 
corpuscles increase in number by division, and the nucleus of each swells up 
into a spherical germinal vesicle, around which is gradually produced the yelk 
of the ovum. In all parts of the young ovary under the germ epithelium, 
groups of germ epithelial corpuscles become imbedded in meshes of the stroma. 
As each individual in the group swells up the nucleus or germinal vesicle 
becomes very distinct as a round or spherical body. From the swelling out 
of each germ epithelial corpuscle in the group, the whole group expands and 
becomes more or less spherical. Such groups of developing corpuscles are 
called egg clusters. Each egg cluster is inclosed is a mesh or capsule of vas- 
cular stroma of the ovary. Each imbedded germ epithelial corpuscle is poten- 
tially an ovum. 
The stroma of the young ovary consists for the most part of fusiform con- 
nective tissue corpuscles and blood-vessels. The walls of the young blood- 
vessels in the young stroma consist of connective tissue corpuscles. The 
connective tissue corpuscles are direct offshoots from the ovarian stroma, and 
are found in contact with the yelk or protoplasm of each primordial ovum 
situated among the germ epithelial corpuscles on the surface of the ovary. 
Wherever we find primordial ova we see connective tissue corpuscles in con- 
VOL. XXVII. PART III. 5 F 
