276 



THE CIRCULATORY SYSTEM. 



appendage, presents externally is due to the muscular thicken- 

 ings of the wall (musculi pectinati). 



Fig. 115. — Heart, Ventral View. Fig. 116. — Heart, Dorsal View. 



Fig. 115. — a, right ventricle; l>, left ventricle; c, right auricular appendage;^, 

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

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

 artery; /, left common carotid; t>i, right common carotid; «, right subclavian; o, 

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



Fig. 116. — a, right ventricle; /', 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; /i, sinistral group; /, dextral grouji); J, pulmonary artery (division into two); 

 i, innominate artery; /, left subclavian; m, left common carotid; ft, 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 



