DIFFERENT FORMS OF CIRCULATING APPARATUS. 241 



Lesser circulation. 



Pulmonary veins 



Pulmonary artery 



Left auricle 



Right ventricle ,' 



Aorta 



Left ventricle 



Greater circulation. 

 Fig. 129. DIAGRAM OF THE CIRCULATION IN MAMMALS AND BIRDS. 



were quite distinct from each other ; and in fact they are 

 almost so in the Dugong, one of the herbivorous Whales- 

 Lesser circulation. 



Heart 



Vena cava 



Aorta 



Single ventricle 

 Greater circulation. 



Fig. 130. DIAGRAM OF THE CIRCULATION IN REPTILES. 

 R 



