ANATOMICAL FEATURES 



19 



EPIDIDYMIS 



VAS DEFERENS 



PI D I Y M I S 



Fig. 9. Various vertebrate testes and reproductive ducts, emphasizing the relative sim- 

 plicity of the duct where external fertilization is the rule while complexity of the duct is 

 present when internal fertilization is utilized. There are exceptions to this rule, however. 

 (A) Flounder (Limanda ferruginea). (B) Frog (Rana catesbiana). (C) Urodele 

 (Cryptobranchiis alleganiensis). (D) Dog shark (Squalus acanthias). (E) Urodele 

 (Nee turns maculosus). (F) Rooster (Gall us doinesticus). 



the epididymal duct may be much longer. For example, in the ram, from 40 

 to 60 m.; in the boar, 62 to 64 m.; in the stallion, 72 to 86 m. (Asdell, '46). 

 At its caudal end it becomes much less tortuous and gradually passes into 

 the vas deferens (ductus deferens). 



The ductus deferens has a length of about 30 to 35 cm. in man. Leaving 

 the scrotum it passes anteriad together with accompanying nerves and blood 

 vessels in the subcutaneous tissue over the front of the pelvic bone into the 

 peritoneal cavity through the inguinal ring (fig. 2). Here it separates from 

 the other constituents of the spermatic cord (i.e., it separates from the nerves 



