PLATE 2 



EXPLANATION OF FIGURES 



14 Transection of ovary, young virgin adult cat (no. 45). The Graafian folli- 

 cles of the presexual period have practically disappeared and those of the adult 

 period are developing. The zona parenchymatosa is well indicated by the ova- 

 rian stroma. Photograph. X 15. 



15 Section of ovary, adult cat (no. 51). The surface of a corpus luteiim is cut. 

 The zona parenchymatosa is occupied by the Graafian follicles in varying stages 

 of development. The zone of primary follicles (cortex) is best indicated at the 

 right and left. Photograph. X 12. 



16 Two primary follicles with adjacent nests of follicle cells. From the inter- 

 mediate zone of ovary no. 20 (14 day), showing 'stage 1' in the development of the 

 irregular medullary follicles. Photograph. X 300. 



17 Developing medullary follicles, 'stage 2.' Ovary no. 29. Photograph-. X 250. 



18 Developing medullary follicle, 'stages.' Ovary no. 29. Photograph. X 250. 

 A nodule of stroma is included between the investing and sheathing follicle 

 cells. Two groups of interstitial cells are seen at the right, between them a small 

 cluster of follicle cells. 



19 Medullary follicle (young), 'stage 4.' The line of junction of the invest- 

 ing follicle mass is shown at the lower right hand corner (arrow). Photograph. 

 X 250. 



20 Similar to figure 19. The line of junction may be seen (j). Note also a 

 nodule of included stroma (.s). Photograph. X 250. 



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