354 DISSECTION OF THE BABBIT. 



edge ; and turn the ventral half inwards, so as to expose the 



cut surfaces. 



i. The cortical substance forms the superficial 

 layer of the kidney; the Malpighian bodies, 

 which are confined to it, give it a dotted 

 appearance. 



ii. The medullary substance, forming the deeper 

 part of the kidney, is radially striated, and 

 consists mainly of the non-glandular parts of 

 the tubules. The inner surface of the medul- 

 lary substance projects as a conical process, the 

 pyramid, on which the tubules open. 



iii. The pelvis is the expanded anterior end of the 

 ureter, which lies in the cavity of the kidney, 

 and receives the urine from the apertures on 

 the pyramid. 



b. The ureters are a pair of slender tubes, running 



back from the kidneys along the dorsal wall of 

 the abdomen, a short distance from the middle 

 line. At the hinder end of the abdomen they turn 

 inwards and open into the bladder, opposite the 

 anterior border of the pubic symphysis. 



c. The bladder is a thin-walled muscular sac, of 



which the anterior end, in front of the pubic 

 symphysis, can alone be seen at this stage of the 

 dissection. 



2. The reproductive system. 



The testes, in early life, lie against the dorsal 

 wall of the abdomen, close to the kidneys. Before 

 maturity, however, they separate from the dorsal 

 wall, and pass through the inguinal canals into the 

 scrotal sacs. 



a, The scrotal sacs are a pair of muscular pouch-like 

 diverticula of the abdominal wall, lying ventral 

 to the pelvis and close to the median plane. Each 



