THE OVA AND OVARY IN MAN AND OTHER MAMMALIA. 301 



these bodies present the appearance as described by 

 Waldeyer. 



(b.) The Relation of the Germ Epithelium to the Peritoneal 

 EpitJielium. — In a section of the ovary of a seven and a half 

 months' foetus, the stalk or peduncle is directly continued into 

 the ovary to form the stroma, which we described as arranged 

 in the form of a mesh-work. If we now direct our attention 

 to the epithelium covering this stalk, we find it is directly 

 continuous with the peritoneal epithelium, and on the other 

 hand passes without a break into the epithelium which 

 covers the ovary, but a gradual change in its character takes 

 place as it slides into and becomes continuous with the 

 latter. 



In the peritoneal epithelium, as seen in profile, the 

 nuclei of the cells are oval and flattened from above down- 

 wards, and are placed at a considerable distance from each 

 other, and the protoplasm around them is extensive. 

 Tracing this epithelium towards the ovary, as we approach 

 the latter, we observe the nuclei of the epithelial cells to 

 become round and columnar, and gradually to lie closer 

 together until at last they are almost in contact. They then 

 crowd together, and in the form of a thick layer pass on to 

 the surface of the ovary as the corpuscles of the germ 

 epithelium. As the corpuscles of the peritoneal epithelium 

 gradually slide into those of the germ epithelium, we find 

 the protoplasm which invests the nuclei of the former 

 gradually becomes less and less in quantity, and the nuclei 

 themselves become gradually larger and more columnar, 

 until at last the nuclei pass on to the surface of the ovary as 

 distinct columnar bodies, each having round it a fine invest- 

 ment of protoplasm. In thus tracing the peritoneal 

 epithelial corpuscles into germ epithelial corpuscles we see 

 the nuclei undergoing fission, and by this process crowds of 

 germ corpuscles are produced. The whole germ epithelial 

 layer must be regarded as a thick layer of proliferating 

 corpuscles. From the first appearance of the ovary as an 

 organ until its development is completed, there is a constant 

 proliferation of the germ epithelial corpuscles ; and in 

 growth of the ovary, as fast as some corpuscles become 

 imbedded in the stroma, others are produced to take their 

 place. 



It is interesting to recal to recollection the statement of 

 Schenk^, Waldeyer, and others, that in the first instance the 

 whole peritoneal cavity is lined by a layer of columnar cor- 

 puscles, and when the Wolffian body appears in connection 

 ' ' Beitiagc zur Lehre von den Organ-Anlagen im motoriscben Keimblatt.' 



