TESTES. 



225 



of canals, the seminiferous tubules, which, on account of the 

 different course they take in different regions, are divided into 

 three parts. The part lying toward the periphery of the organ 

 forms the much-convoluted tubuli contorti. These join with 

 one another and make up the tubuli recti, which near the 

 mediastinum break up to form a network, the rete testis (Hal- 

 leri). 



FIG. 174. 



Epididymis 



Blood- 

 vessels 



J Highmori 

 W and rete 



testis 



Tuni 



albugin 



Tunica 

 vasculosa 



Transverse section of the testis of a two and a half year old boy. X 7. 



The tubuli contorti in the human adult are very long 

 canals, about 140-250 // in diameter, and form the most 

 important part of the testis parenchyma, inasmuch as they 

 give rise to the spermatozoa. At the periphery of the testes 

 many of the tubules anastomose and form a closed system. 

 Others, on the contrary, begin blindly. The walls of these 

 convoluted tubules consist of several layers of epithelial cells, 



15 



