338 DISSECTION OF THE RABBIT 



The spermatic arteries and veins, which 

 supply the testes, enter the epididymes at their 

 anterior ends. 



d. The vasa deferentia are a pair of whitish tubes one of 



which arises from each cauda epididymis and runs 

 forwards, alongside the testis, to enter the abdo- 

 minal cavity through the inguinal canal. Within 

 the abdomen it loops round the ureter from the 

 outer to the inner side, and runs back to the neck 

 of the bladder. The hinder part of its course 

 is sinuous, but further forwards it becomes 

 straighter. 



The vasa deferentia are the modified meso- 

 nephric ducts of the embryo. 



Dissect both scrotal sacs from the abdominal wall, and 

 turn them forwards with the testes and vasa deferentia. 

 Determine with the finger the boundaries of the pubes and 

 ischia. Gut longitudinally through the muscles ventral to the 

 pelvis, about half an inch from the middle line on each side, 

 and down to the hone. Scrape clean the descending ramii of 

 the pubes and ischia, and cut through them with bone-forceps 

 in front of, and behind, the obturator foramen on each side. 

 Remove thepehic symphysis, which is now isolated; carefully 

 dissecting it from the underlying parts. Note the corpora 

 cavernosa, a pair of ha/rd ligamentous bodies running back- 

 wards from the hinder border of the ischia to the penis ; and 

 cut them across close to the ischia. 



Inflate the bladder and urino-genital canal by a blowpipe 

 inserted into the terminal aperture of the penis, and tie a 

 Ugatu/re round the penis half an inch from its end, to prevent 

 the air escaping. 



Clean the various structures in the order given below. 



e. The urino-genital canal, or urethra, is the continua- 



tion backwards of the neck of the bladder, through 

 the pelvic cavity. It is a straight tube, with thin 

 and very vascular walls, which lies immediately 

 dorsal to the pelvic symphysis, and ventral to the 



