PHYTA T M PLATYHELMINTHES 



237 



B short mouth-cavity into a cylindrical thick-walled chamber, the 

 pharynx {ph.), which is highly mobile, and is capable of being 

 thrust out as a, proboscis through the mouth, beyond which it 



l.n€> 



Fig. 182.— Planaria. Digestive and excre- 

 tory systems, ex. openings of excretory 

 system ; int. intestine ; mo. mouth ; 

 o. ph. opening of pharyi IX, (After Jijinia 

 and Hatschek.) 



Fkj. 183.— Planaria. Nervous system. 

 br. brain ; eye, eye ; /. ne. longitu- 

 dinal nerve ; ph. pharynx. (After 

 Jijima and Hatschek.) 



may then be extended to a relatively considerable distance. 

 When retracted it lies within an enclosing muscular sheath. The 



