60 



THE VERTEBRATE OVARY AND ITS RELATIONSHIP TO REPRODUC 1 ION 



SECONDARY FOLLICLE 

 PRIMARY FOLLICLE 

 GERMINAL EPITHELIUM 

 wyEGG NEST 

 MESOVARIUM- 



MEDULLA "^ (i " 



ANTRAL VACUOLE 



TERTIARY FOLLICLE 



TUNICA ALBUGINEA 



MATURE 



FOLLICLE 



CORP 

 ALBICANS 



FLUID- FILLED 

 ANTRUM 



CORPUS LUTEUM 



OVUM 

 CONNE CT VE TISSUE 



RUPTURED FOLLICLE 



OVUM WITH CUMULUS 



CELLS 



FOLLICULAR FLUID 



Fig. 30. Schematic three-dimensional representation of the cyclic changes which occur in 



the mammalian ovary. 



carrying the interstitial tissue and immature ova. This shrinking away of the 

 tissues of the ovary leaves a space between these tissues and the outside 

 ovarian wall. A lumen thus is formed along the lateral aspect of the ovary 

 which is continuous with the oviduct. Many teleosts have two ovaries (e.g., 

 flounder); in others there is but one (e.g., perch). 



The amphibia possess a true saccular ovary (fig. 32). It has a cortex and 

 germinal epithelium somewhat similar to the compact ovarian variety, but 

 the area which forms the medulla in the compact ovary is here represented 

 by a large lymph space. During early development, the amphibian ovary is 

 a compact structure, but later there is a hollowing out and disappearance of 

 the compact medullary portion, and the cortical area remains as a relatively 

 thin, peripheral region (Burns, '31; Humphrey, '29). 



Histologically the vertebrate ovary is composed of two general cellular 

 groups, namely: 



( 1 ) germ cells, and 



(2) general tissue cells of various kinds, such as epithelium, connective 

 tissue, smooth muscle fibers, and the complex of elements compris- 



