i6o THE PHYSIOLOGY OF REPRODUCTION 



convoluted tube situated at the posterior margin of the organ and 

 attached to the mediastinum. This is the epididymis. Its lower 

 extremity is prolonged into a thick-walled muscular tube (the vas 

 deferens) which is the passage of exit for the seminal fluid or 

 sperm-containing secretion. The glandular substance of the testis 

 is composed of the convoluted seminiferous tubules, two or three 

 of which join together to form a straight tubule which passes into 



Fig. 46. — Section through human testis and epididymis. (After Bohni 

 and von Davidoff, from Schafer.) 



a, Glandular substance divided into lobules by septa of connective tissue ; 

 6, tunica albuginea ; c, part of epididymis ; d, rete testis ; e, body of 

 epididymis ; /, mediastinum ; g, sections through commencing portion 

 of vas deferens. 



the body of the mediastinum. The straight tubules within the 

 mediastinum unite in their turn, giving rise to a network of vessels 

 called the rete testis. From the rete the vasa efferpntia are given 

 off. Between the- tubules is a loose connective tissue containing 

 a number of yellow epithelioid interstitial cells. The connective 

 tissue also contains numerous lymphatics and blood-vessels (branches 

 of the spermatic artery). The nerves of the testis are derived from 

 the sympathetic system, but a few filaments come from the hypo- 

 gastric plexus. 



