16 



(6) The opening into the pulmonary artery, guarded by three semi- 

 lunar cusps. 

 (2) The left ventricle. Remove its outer wall, and note — 



(a) The mitral valve (bicuspid) of the left auriculo-ventricular 



opening, corresponding in structure to the tricuspid valve, but 

 with larger musculi papillares. 



(b) The muscular ridges of the wall of the ventricle (columnSB 



carneae). 



(c) The opening into the aorta guarded by three semilunar valves. 

 [Note also the opening of the coronary arteries.] 



Qt, Dissection of the Urinary and Reproductive Systems. 

 The male rabbit. 



1. The urinary system. Examine one of the kidneys, noting (1) its 



ovoid shape ; (2) the hilum, or point of entrance of the vessels and 

 ureter. Make a longitudinal section, and note — 

 (a) The cortical substance forming the outer layer. 

 (6) The medullary substance. 



(c) The pjrramids, conical papillae. 



(d) The pelvis, or expanded anterior end of the ureter. 



Trace the ureter from the kidney to the bladder. Note the general form 

 and the thin wall of the bladder. 



2. The reproductive system. Open the scrotal sacs along their ventral 

 surface. Note — 



(a) The testes, with the spermatic veins and arteries entering at 



their anterior ends. 



(b) The epididymes, masses of convoluted tubes lying along the inner 



border of the testes. 



(c) The vasa deferentia, a pair of whitish tubes extending from the 



epididymes, to enter the abdominal cavity where, after looping 



round the ureters, they reach the neck of the bladder. 



Inflate the bladder and the urino-genital canal, from the urethra : remove 



the symphysis pubis by cutting through the bones about a quarter of 



an inch from the middle line : detach the two crura penis from the 



ischia, and make out the following structures — 



(a) The urino-genital canal, the continuation posteriorly of the 



neck of the bladder. 



(b) The penis, with the corpora cavernosa dorsally, and the corpus 



spongiosum ventrally pierced by the urethra. 



(c) The uterus masculinus, a somewhat bi-lobed median sac 



projecting from the dorsal surface of the urino-genital canal. 



(d) The openings of the vasa deferentia, on the ventral wall of 



the uterus masculinus. 



(e) The prostate, a glandular body connected with the neck of the 



bladder and the uterus masculinus. 



