THE VASCULAR SYSTEM 



355 



walls, meet, and fuse. This causes a complete separa- 

 tion of these main vessels as far back as the ventricle, and 

 their exits from this chamber are placed in such a way that 

 the blood from the right side, which is mainly imgure, passes 



FIG. 102. Diagrams of the heart and its compartments in the different 

 vertebrate Classes. [In part after WIEDERSHEIM.] 



(A) Fish; (B) Urodele; (C) Anuran; (D) Reptile; (E) Bird; (F) Mammal. 



