242 . THE BIOLOGY OF THE ANIMAL 



far from the heart do the arteries arise ? How far 

 apart? Trace the anterior artery, the common 

 carotid, to the point where it subdivides into the 

 external carotid or lingual artery and the 

 internal carotid artery. What course does each 

 take ? What is the position of the lingual artery 

 with regard to the external jugular vein ? Of the 

 internal carotid artery with reference to the in- 

 ternal jugular vein ? Near the base of the lingual 

 artery find a small swelling, the carotid gland. 

 Make a diagram of the carotid or aortic arch and its 

 branches. 



Study next the systemic arch. Trace either half, 

 dorsally and posteriorly, to the anterior end of the 

 kidney, where it unites with the corresponding 

 artery from the other side and forms the dorsal 

 aorta. Still farther back it divides into the 

 iliac arteries. How long is the aortic arch ? 

 How long is the dorsal aorta ? At what point do 

 the iliac arteries arise ? In which direction do they 

 run ? Given off by the aortic arch find the sub- 

 clavian artery. In which direction does it run ? 

 What is its relation to the subclavian vein ? Find 

 also the vertebral artery. What is its position? 

 Note its branches. How are they arranged ? How 

 many are there? To what parts do they run? 

 At or near the point where the dorsal aorta 

 arises look for the stump of a branch, the coeli- 

 aco-mesenteric artery, which runs to the ali- 

 mentary canal. Trace the branches of this blood- 

 vessel to the various digestive organs. Farther 

 back find the urino-genital arteries. From 

 what part of the dorsal aorta do they arise ? How 

 many are there ? Kunning to the large intestine 



