THE RABBIT. 123 



(b) The right and left common carotids, sending 

 blood to the head. They are called common carotids 

 because each divides into an external carotid, carry- 

 ing blood to the outside of the head, and an internal 

 carotid, carrying blood to the brain and inside of the 

 head. From what artery do these spring? Do they 

 leave the artery separately or together? 



(c) The left subclavian, carrying blood to the left 

 fore leg. 



5. Trace the aorta until it becomes the dorsal 

 aorta, previously seen. 



6. Find on each side of the neck a large vein, the ju- 

 gular vein. Trace it towards the heart until it unites 

 with a vein from the left fore leg, the subclavian 

 vein. 



7. The union of the jugular and the subclavian 

 veins forms the superior vena cava. Find one on 

 each side of the body. 



8. Cut off the arteries and veins as far from the 

 heart as you can, and remove the heart and lungs 

 from the thorax. What holds the lungs in place? 



9. Notice the trachea. Find the larynx, at the top. 

 How many rings has the trachea? Do the rings go 

 entirely around? What is tlie position of the 

 oesophagus, with reference to the trachea? 



10. Notice the bronchial tubes. Where does each 

 lead? 



11. Find the pulmonary artery, leading from the 

 heart to the lungs. Find where it branches to each lung. 



12. Find the pulmonary veins, leading from the 

 lungs to the heart. How many? 



13. Identify the right and left auricles and the 

 right and left ventricles. With which chamber of the 

 heart does each artery and each vein that you have 

 seen communicate? 



14. M&ke a complete diagram of the circulation of 

 the rabbit. 



