404 THE CORPUS LUTEUBI OF DASYUllUS, 



rarefied, and numbers of atrophic follicles are seen in various places. The 

 dark lines in the corpora lutea themselves represent vascular spaces filled 

 with blood, and darkly stained with hematoxylin. A few large blood vessels 

 are also seen in the centre of the ovary. 



Fig. 18. — An atresic follicle in an early stage of degeneration ( x SO) 

 Note that the retinacula are dissolved, and that the interior of the follicle 

 is partly filled with coagulum, containing small darkly stained granules. In 

 the original specimen the basal membrane was still distinguishable outside 

 the atrophic membrana granulosa. 



Plate xvi. 



Fig. 19 shows one large and two small atresic follicles ( x 50). 



The large follicle has the remnant of the ovum, with some of the coagulum 

 of the liquor folliculi for its contents. The cells of the membrana granulosa 

 are degenerating, and the basal membrane has disappeared. The two smaller 

 atresic follicles show the ovum in the centre, and a single layer of epithelium, 

 set upon a basal membrane, which is distinct in places. 



Fig. 20.— An atresic follicle ( x 130). 



This figure shows the degenerated ovum and coagulum in the cavity of 

 the follicle. It also shows the degenerating membrana granulosa indistinctly 

 separated (in the upper half) from the theca folliculi. The rarefaction of the 

 ovarian stroma is also well shown (below and to the right). The rest of the 

 figure is occupied by corpora lutea. 



Plate xvii. 



Fig. 21 shows a number of atrophic follicles with portions of two young 

 corpora lutea ( x 130). 



Above is seen the surface epithelium of the ovary. A little below are seen 

 three atrophic follicles, the middle one being the most interesting. It shows 

 centrally a lightly stained mass with darkly stained spots, the whole having the 

 appearance of a plasmodium under the microscope. The mass represents the 

 remnant of the ovum invaded by leucocytes. Immediately external to the 

 mass is a zone of darkly stained cells, which under a high power are seen to 

 be somewhat fusiform, and resemble cells of connective tissue. These 

 were originally membrana granulosa cells which are probably undergoing a 

 metaplasia, as described in the text. Outside this zone of darkly stained 

 cells (seen best above) is a zone of cells which represents the theca folliculi. 

 Portions of young corpora lutea are seen below, and three old atrophic 

 follicles in the interval between. 



Plate xviii. 



Fig. 22 shows sections of three corpora lutea, two of which are "true," 

 and one (the central) is a corpus luteum atreticum ( x 50). 



