THE VASCULAR SYSTEM. 147 
The pulmonary veins convey the pure blood from the 
lungs to the left auricle. There are three main trunks from 
each lung. These six veins are arranged in pairs (Fig. 71), 
constituting a left pair from the left lung; a median pair, 
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anan 
crag 
spm Lim spin | 
Spin 
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Fic. 79. A, VENTRAL View OF Heart AND MAIN ARTERIES IN THE TRUNK 
OF THE Rassit. B, ARTERIES oF Man. 
a, Right auricle; ca, left carotid; c. ax, coeliac a z. n, innominate; 
il, common ‘iliac; i. m, inferior mesenteric: , left renal; r. 7, 
right renal; 7. c, right ‘intercostals ; sm, ae mesenteric; spm, 
spermatic; sa, sacral ; sb, left subclavian. 
composed of one branch from the right and one from the 
left lung; and a right pair from the right lung. Each pair 
forms a common trunk before entering the auricle. In 
order to demonstrate these veins one must remove the heart 
