CIRCULATION 



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FIG. 114. Diagram to show the general plan of the circulation in mammals, 

 i, Left ventricle; 2, aortic arch; 3, dorsal aorta; 4, postcaval vein; 5, right 

 auricle; 6, right ventricle; 7, pulmonary artery; 8, pulmonary veins (the pul- 

 monary veins open into the left auricle which in turn opens into the left ventricle). 

 The order of the numbers 1-8 indicates the course taken by the blood in com- 

 pleting a circuit of the systemic and pulmonary circulations. 10, the thoracic 

 (lymphatic) trunk; n, precaval vein. Dig., The digestive tract; H.P.V., 

 hepatic portal vein; Liv, liver; P, lung. 



