246 ANATOMY OF THE RABBIT 



ing smooth muscle fibres, intimately associated with the 

 lower end of the epididymis (e), joins the posterior end of 

 the testis with the end of the sac. 



(d) The visceral layer (lamina visceralis) of the tunica vagi- 

 nalis propria forms the peritoneal coat of the testis and is 

 continuous with the mesorchium, a broad vertical fold of 

 peritoneum connecting the testis dorsally and anteriorly 

 with that of the body-wall. 



(e) The first portion of the duct of the testis, the epididymis, 

 is very long, slender, and much coiled, the coils being 

 bound together by connective tissue to form a thickened 

 mass, usually imbedded in fat, fitting like a cap over the 

 anterior end of the testis. It then extends back as a thinner 

 cord along the side of the latter body and of the guber- 

 naculum. The thickened anterior part is the caput 

 epididymidis, the more slender part beside the posterior 

 end of the testis and the gubernaculum is the cauda 

 epididymidis, while the still thinner intervening portion 

 is the corpus epididymidis. The second portion of the 

 duct, the ductus deferens, leads forward from the cauda 

 epididymidis, where it is firmly attached to the guber- 

 naculum. The connection with the epididymis may be 

 shown by carefully separating the duct from the guber- 

 naculum and the side of the testis. The ductus deferens 

 receives its blood supply mainly by the arteria deferentialis, 

 which originates from the base of the umbilical artery or 

 from the immediately adjacent part of the common iliac 

 artery. 



(/) The internal spermatic artery (a. spermatica interna) 

 arises from the abdominal aorta, in the neighbourhood of 

 the inferior mesenteric artery, or opposite the sixth lumbar 

 vertebra, the left artery usually behind the right. It sends 

 branches to the epididymis and ductus deferens, and then 

 follows a greatly contorted course to the anteromedial part 

 of the testis, on the surface of which it then coils back and 

 forth before finall^^ entering its substance. The tortuous 

 course of the artery appears to be an arrangement for 

 slowing the blood flow. 



