
IN MAN AND OTHER MAMMALIA. 353 
by the swelling out of the nucleus. In the two weeks’ old kitten the corpuscles 
of the ovarian germ epithelium are several deep, and the layer itself is of 
irregular thickness. 
As we examine the layer of germ epithelium as it passes round the ovary, 
we are at once struck by the fact that the corpuscles present a great variation 
in size and degree of development. Here and there we see large spherical 
nuclei (/,/, 7), having round them a thin investing layer of protoplasm, while 
in other situations certain individual corpuscles stand forth prominently among 
their neighbours, and are conspicuous by their size and the size of their nuclei 
(m,m.) In these latter the protoplasm surrounding the nuclei is in the form 
of a thick layer. Between these largest corpuscles and the ordinary small ones 
every variety in size and form is to be met with. The largest corpuscles, which 
present so much protoplasm round the nucleus, are evidently individuals which 
have reached an advanced stage of development. These have been termed 
primordial ova, and there can be no doubt that a great number of the larger or 
spherical germ epithelial corpuscles are developing into similar bodies. 
The ordinary sized germ epithelial corpuscles measure about y;‘j59th of an 
inch, while the primordial ova measure about +y,qth of an inch, but these 
measurements vary. 
On carefully examining the primordial ova, in many instances two or more 
small fusiform corpuscles are seen in close contact with their yelk or protoplasm. 
These fusiform bodies are about the size of the smallest germ epithelial cor- 
puscles, and appear like connective tissue corpuscles, and in more than one case 
I have traced them in direct continuity with delicate bundles of minute fusiform 
bodies, which will presently be described as passing up from the deeper parts 
of the ovary towards the germ epithelium. In other cases, however, it appears 
to me that the bodies which lie in contact with the protoplasm of the primor- 
dial ova are germ epithelial corpuscles which have been displaced, pushed 
aside, or flattened out during the growth of the primordial ova. No cell wall 
¢an be made out round these primordial ova, but in certain sections one fre- 
quently sees a thin irregular stratum of a hyaline substance passing round the 
young ovum in contact with its protoplasm, apparently growing up from the 
young connective tissue subjacent to the germ epithelium. In this hyaline 
substance two or three oval-shaped nuclei are seen. In some preparations 
the primordial ovum has tumbled out of its hyaline girdle, which remains like 
a ring standing up among the germ epithelial corpuscles. 
In favourable specimens, in a single section of a three to four weeks old 
kitten’s ovary, I have counted as many as from thirty to forty large primordial 
ova among the ordinary germ epithelial corpuscles on the surface of the ovary. 
‘They may be recognised at once, for they appear like giants among their 
neighbours. Each consists of a large spherical nucleus, surrounded with a con- 
VOL. XXVII. PART IIL. &z 
