Il8 ANATOMY OF THE RABBIT 



supply of the penis. After the rectum has been studied, it may 

 be probed with the grooved director and sHt open. Note the 

 ridges (rugae) in its Hning and the sphincter ani muscle. 



Work out the relations of the ureters, urinary bladder, 

 seminal ducts (vasa deferentia, singular number, vas deferens) 

 urethra, prostate gland, and seminal vesicles. Method: 

 Beginning on the ventral side at the neck of the bladder 

 carefully separate the urethra from the seminal ducts, the 

 seminal ducts from the large somewhat bilobed seminal vesicle 

 and the vesicle and prostate gland, from the rectum about 

 three cm., or more, caudad. Slit the prostate gland and seminal 

 vesicle along the dorsolateral side in order to see the size and 

 urethral orifice of the seminal vesicle, the points of entrance 

 of the seminal ducts into this vesicle, which form two papillae 

 near the orifice, and the relations of the prostate gland. The 

 seminal vesicle is a large sac in which spermatozoa are almost 

 continuously stored and from which the spermatozoa are 

 normally forcefully ejected (ejaculated) during copulation. 

 The seminal vesicle occurs only in the male in any species and 

 must not be confused with the sperm receptacle (spermatheca) 

 which is a structure found in the female of many animals, such 

 as bees, flies, certain hermaphroditic snails and other forms, 

 and receives the spermatozoa from the male during copulation. 

 Separate the urethra from the rectum caudad to the anus. 



Cowper's (bulbourethral) gland is bilobed and lies on the 

 dorsolateral sides of the urethra just caudad to the orifice of the 

 seminal vesicle. The function of the bulbourethral gland 

 appears to be only that of furnishing a lubricating fluid to 

 facihtate copulation; however, some physiologists maintain 

 that its chief function is to keep the seminal fluid alkaline. The 

 prostate gland contributes its secretions to the seminal fluid and 

 probably has an endocrine function. 



The rectum should be slit open in order to observe the 

 longitudinal rugae and the circular muscles which form the 

 sphincter ani valve. The large anal glands lie on either side 

 of the anus. 



