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THE FLATWORMS— PLATYHELMINTHES 



For excretion, however, we find a system has been developed. Scat- 

 tered over the body there are many flame cells that pick up the waste 

 products of metabolism as they are thrown off by the individual cells. 

 A flame cell is shaped like a funnel with cilia around the mouth ; these 

 beat so as to suck the excretory products down into the funnel, somewhat 





Nerve branches 



Nerve cord 



Fig. 10.5. The nervous system of planaria. Note the ladder-like appearance of the 

 two nerve cords with the connecting nerves between them. 



