366 



THE ORGANS 



these granules that the characteristic yellow color of the corpus 

 luteum is due. A dehnite cellular structure with a supporting con- 

 nective-tissue framework thus replaces the corpus htcmorrhagicum, 

 remains of which are usually present in the shape of orange-colored 

 crystals of haematoidin. By degeneration and subsequent absorption 

 of its tissues the corpus luteum becomes gradually reduced in size, 



Corona 

 radiata 



Volk 

 granules. 



Zona 

 pellucida 



Fig. 258. — From a Section of a Human Ovum. Section taken from the ovary of a 

 12 year old girl. The ovum lies in a large mature Graafian follicle and is surrounded 

 by the cells of the "germ hill" (the inner edge of which is shown in the upper left-hand 

 corner of the figure). Photograph. (Bailey and ^Miller.) 



loses its yellow color, and is then known as the corpus albicans. This 

 also is mostly absorbed, being finally represented merely by a small 

 area of fibrous tissue. 



Corpora lutea are divided into true corpora lutea (corpora lutea 

 vera or corpora lutea of pregnancy) and false corpora lutea (corpora 

 lutea spuria); The former replace follicles whose ova have under- 

 gone fertilization, the latter, follicles whose ova have not been fer- 



