106 



ORGANS OF THE THORAX. 



around and between the air sacs. These capillaries receive 

 their blood from the pulmonary artery, and return it to the 

 heart by the pulmonary veins. 



1. Pulmonary Orifice 



2. Aortic Orifice 



3. Left Auriculo-Ventricular Orifice 



4. Right Auriculo-Ventricular Orifice 



Fig. 40. Front View of the Thorax. The Ribs and Sternum are Represented in 

 Relation to the Lungs, Heart, and other Internal Organs. 



