X URINOGENITAL ORGANS 521 



which the kidney is composed (p. 146) converge to open 

 into a wide chamber ox pelvis, which forms the dilated com- 

 mencement of the ureter. When the kidney is cut across, 

 its substance is seen to be divided into a central mass or 

 medulla and a peripheral portion or cortex. The former 

 appears radially striated, owing to the tubules in this region 

 being straight and converging to open on the surface of a 

 conical process or pyramid, which projects into the pelvis : 

 the cortex contains the coiled portions of the tubules and 

 the Malpighian bodies, and thus has a dotted appear- 

 ance. The ureter (Figs. 125 and 134, ur^ runs backwards 

 along the dorsal wall of the abdomen to open into the 

 urinary bladder (u. bl, bt), a pyriform sac with elastic walls 

 which vary in thickness according as the organ is dilated or 

 contracted : in the male the openings of the ureters are 

 situated nearer the posterior, narrower end or neck than in 

 the female. Near the front end of each kidney, towards its 

 inner side, is a small yellowish adrenal or supra-renal body 

 (Fig. 1 25, adr). 



In the male Rabbit the spermaries are oval bodies which 

 in the young animal are situated close to the kidneys, on the 

 dorsal wall of the abdomen, but which pass backwards and 

 downwards as the animal approaches maturity until they 

 come to lie each in a scrotal sac (p. 470), situated at the side 

 of the urinogenital opening. The cavity of each scrotal sac 

 is in free communication with the cavity of the abdomen by 

 an opening — the inguinal canal. A convoluted epididymis 

 (p. 451), closely adherent to the spermary and connected 

 with the distal end of the scrotal sac, forms the proximal 

 part of the spermiduct or vas deferens (Fig. 134 A, v. d), 

 which, together with the blood vessels and nerves of the 

 spermary, passes through the inguinal canal : it then loops 

 round the corresponding ureter, and extends back between 



