276 



THE CIRCULATORY SYSTEM. 



appendage, presents externally is due to the muscular thicken- 

 ings of the wall (musculi pectinati). 



Cw\ 



FIG. 115. HEART, VENTRAL VIEW. FIG. 116. HEART, DORSAL VIEW. 



Fig. 115. a, right ventricle; b, left ventricle; f, right auricular appendage; d, 

 left auricular appendage; e, conus arteriosus; f, pulmonary artery; g, aortic arch; 

 A, thoracic aorta; i, vena cava superior; /, innominate artery; k, left subclavian 

 artery ; /, left common carotid ; m, right common carotid ; n, right subclavian ; o, 

 azygos vein; /, the two innominate veins; y, coronary artery. 



Fig. 116. a, right ventricle; b, left auricle; c, right auricle; d, vena cava in- 

 ferior; e, vena cava superior; f, aorta; g, h. i, groups of pulmonary veins (g, dorsal 

 group; h, sinistral group; /, dextral group); /, pulmonary artery (division into two); 

 ., innominate artery; /, left subclavian; m, left common carotid; n, right common 

 carotid; o, right subclavian; /, azygos vein. 



The cavity (including that of the auricular appendage) is 

 somewhat egg-shaped, with its long axis transverse. The 



