XXXII.] TISSUES OF EEPBODUCTION. 339 



Probably most of the stages between the small- 

 est and the largest follicles will be seen in the 

 specimen. 



d. Granular polyhedral cells in the stroma some- 

 thing like those that occur in the interstitial 

 tissue of the testis. 



e. In some of the sections taken near the hilus 

 there may be seen lying in the stroma groups 

 of tubules, lined with a short cubical or 

 flattened epithelium, and cut at various angles. 

 These are the tubules of the parovarium. 



3. Take the fresh ovary of a sheep or large dog ; 

 observe the bulgings due to the more or less 

 ripe Graafian follicles. Holding the ovary over 

 a glass slide, carefully prick the most prominent 

 follicle and receive the contents on a glass slide. 

 Examine without a cover slip, with simple lens 

 or low objective. If the ovum is present it will 

 at once be recognized. When one is obtained 

 carefully cover with a cover slip, inserting a ring 

 of paper in order to avoid pressure, and examine 

 with a high power. Observe 



a. The thick zona pellucida, with double contour 

 (and radiating striation). 



b. The granular cell-substance (vitellus). 



c. The transparent germinal vesicle, with its 

 germinal spot. If the follicle be quite ripe 

 these may have disappeared. 



d. The cells of the cumulus proligerus attached 

 all round the zona pellucida. 



22—2 



