iH THE CIRCULATION. 



forming by their union two large trunks, called the superior 

 and inferior vena cava, discharge their contents into the 

 right auricle, whence we supposed the blood to start (fig. 3 3). 



Structure of the Valves of the Heart. 

 It will be well now to consider the structure of the 



* Fig. 34. The right auricle and ventricle opened, and a part of 

 their right and anterior walls removed, so as to show their interior. \. 

 i, superior vena cava; 2, inferior vena cava; 2' hepatic veins cut 

 short; 3, right auricle; 3', placed in the fossa ovalis, below which is 

 the Eustachian valve ; 3 /x , is placed close to the aperture of the coronary 



