206 WILLIAM WALLACE. 



just described were present, the corpora lutea of the formei 

 specimen may be about one year old. 



Sections of the advanced corpus Inteum of Spin ax are 

 shown in figs. 31 and 32. The corpus hiteum is much 

 smaller than the recently ruptured follicle described above. 

 Another obvious point of difference is that its cavity is full 

 of blood-corpuscles. The latter are also present in great 

 numbers in all the lymph spaces of this particular ovary. 

 On the other hand, no blood was found in the spaces of the 

 other ovary of Spin ax previously spoken of. 



The more advanced corpus luteum of Spinax (figs. 31, 32) 

 exhibits a more decided resemblance to the mammalian 

 corpus luteum, as described by Sobotta. His account of 

 what takes place in the mouse may be thus briefly sum- 

 marised. After bursting of the follicle, mitoses in the 

 follicular epithelium cease, but the cells of the theca 

 interna proliferate and grow into the layer of hyper- 

 trophied follicular epithelium in the form of radial trabeculas 

 of connective tissue with blood-vessels. In the cavity of the 

 ruptured follicle there is at first an effusion of blood, but this 

 is absorbed later, and " Wanderzellen,'^ together with con- 

 nective-tissue cells, form a network which occupies the 

 centre of the corpus luteum. This central nucleus of con- 

 nective tissue is connected with that of the thecal wall by 

 the radial trabecule just alluded to. The arrangement of 

 the connective tissue in transverse sections recalls the rela- 

 tions of the parts of a wheel, of which the axle, spokes, and 

 rim are composed of connective tissue, and the spaces 

 between the spokes filled with the hypertrophied follicular 

 epithelium. Thus the obliteration of the original egg-cavity 

 of the follicle is brought about by a complicated process, 

 probably assisted by the actual contraction of the walls of 

 the follicle. The characteristic epithelial portion of the 

 corpus luteum arises by simple enlargement of the primitive 

 follicular epithelium. The connective-tissue portion is formed 

 by a proliferation (with karyokinesis) of the inner thecal 

 sheath. Marshall's account (1901) of the corpus luteum in 



