332 DISSECTION OF THE EABBIT 



i. The ilio-lumbar artery runs outwards along 



the posterior part of the dorsal wall of the 



abdomen, 

 ii. The internal iliac artery runs backwards along 



the dorsal wall of the pelvic cavity, 

 iii. The vesical artery is a small branch which runs 



backwards to the bladder. In the female it 



also supplies the uterus. 



4. The pulmonary artery has already been described 



(p. 324j. 

 Follow the branches of the pulmonary artery into the lungs. 



D. The Thoracic Duct. 



The thoracic duet is a slender thin-waUed tube running 

 forwards through the thorax, and lying immediately to the 

 left of and dorsal to the aorta. Between the third and 

 fourth ribs it expands somewhat, and then turning inwards 

 traverses the thymus and opens into the left anterior vena 

 cava close to the left subclavian vein. 



The thoracic duct receives lymphatic vessels &om almost 

 all parts of the body, and places these in communication with 

 the venous system. 



E. Dissection of the Heart. 



Cut across the great vessels, about half an inch from the 

 heart. Bemove the heart, and pin it down under water with 

 the dorsal surface upwards, passing the pins through the ven- 

 tricles and the arch of the aorta. Clean carefully the roots 

 of the several vessels. 

 1. The auricles. 

 Gut away the outer walls of both auricles so as to expose 

 their cavities. Wash out the contained blood. 



a. The right auricle. The wall of the auricle is thin ; 

 that of the auricular appendix is thicker, and 

 is marked internally by muscular ridges, 

 i. The orifices of the venae cavae. 



The right anterior vena cava opens into 

 the anterior part of the auricle. 



