152 



PHYSIOLOGY OF FARM ANIMALS 



[CH, 



organ is comijosed of the seminiferous tubules which are sejjarated 

 from one another by epitheHoid interstitial cells (see p. 164). The 

 tubules contain several layers of epithelial cells supported ex- 

 ternally by a basement membrane. On the internal surface of the 

 basement membrane are the spermatogonia. Certain of the 





^ ^^e-/^-\\ . -c 



■0 1 



< 



^ 



-f 



Fig. 74. Section through testis (from Marsiiali). a seminiferous tubules, h inter- 

 stitial tissue, c rete testis, d vasa efferentia, e vas deferens, / tunica albuginea. 



epithelial cells between the sjjermatogonia are enlarged and pro- 

 ject among the more internal cells in association with developing 

 sjoermatozoa. These are the cells of Sertoli. They are believed to 



