THE HEART. 



103 



these are each again divided laterally into two cavities, the 

 superior called the auricle, and the inferior the ventricle. The 

 auricles take their name from a flattened appendage which 



Fig. 26. Heart and principal arterial and venous trunks. 



A. Rigiit ventr'cle. 



B. Left ventricle. 



C. RigJit auricle. 



D. Left auricle. 



E. Aorta. 



F. Pulmonary artery. 



G. Brachio-cephalic trunk. 

 H. Carotid, right and left. 

 I, I. Subclavian arteries. 

 K. Superior vena cava. 

 L. Pulmonary veifis. 



falls down upon their external face. The right auricle com- 

 municates with the right ventricle, and the left auricle with the 

 left ventricle. There is no communication between the ven- 

 tricles, but before birth the two auricles communicate by an 

 orifice, which is obliterated during the first months of life, 



