ANATOMV AND FUysiOLOGY OF MOLLUfiCA 203 



Organs of Circulation. — In mollusks there is a dorsal heart 

 usually consisting of two chambers: one, the auricle (Fig. 196, 

 aur), receives the blood from the respiratory organs ; the other, 



g'..^£ a 



a j>4; 



the ventricle (vent), pumps it onward to the different parts 

 of the body. In the snail the circulation is as follows : The 



