
IN MAN AND OTHER MAMMALIA. 379 
described by Priticer, SPrEGELBERG, and WaLpryerR. The appearance of 
tubular structures passing into the stroma of the ovary are produced by sections 
through furrows and depressions between irregular prominences on the surface 
of the foetal ovary. The irregularities of the surface of the foetal ovary are pro- 
duced at first by the expansion of egg clusters upwards under the germ epi- 
thelium. Where the walls of furrows and depressions come in contact, egg 
clusters are formed by the imbedding of germ epithelial corpuscles in that 
situation, just as in other situations. Egg clusters are formed in connection 
with the germ epithelium lining the furrows and depressions. Among the germ 
epithelial corpuscles lining the furrows, &c., we find large primordial ova, and 
corpuscles in all stages of development into the same, just as in other situations 
among the ordinary germ epithelial corpuscles. 
In the human foetus, round and oval-shaped groups of germ epithelial cor- 
puscles are found in connection with the germ epithelium all round the ovary. 
When vertical sections are made through these they present the appearance as 
if tubular structures filled with developing germ epithelial corpuscles passed 
from the germ epithelium downwards into the stroma of the ovary. 
The development of the corpuscles of the membrana granulosa, from con- 
nective tissue corpuscles of the stroma, can be well followed out in the ovaries 
of adult rabbits and cats. 
At the age of six years the epithelium on the human ovary consists of very 
small flat hexagonal-shaped corpuscles, measuring z;),5th to zs/59th of an inch. 
The corpuscles are undergoing division. This layer can be stripped offwith- 
out difficulty. At the age of twelve the epithelium has little difference in 
appearance from the above, the small size of the epithelial corpuscles being 
remarkable. The epithelium is beautifully seen in old cats, and must be 
regarded as homologous with the peritoneal epithelium. In old cats the 
epithelium on the surface of the ovary consists of very small distinct cells, mea- 
suring from z_ypth to sooth inch, with granular oval nuclei. 
