PHYLUM PLATYHELMINTHES 



223 



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

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





L.r.c 



./J/l s 



171, Planar ia. Digestive and excre- 

 tory systems, ex. openings of excretory 

 system ; int. intestine ; //<. month ; 

 n. ph. opening of pharynx. (After Jijima 

 ;md Hatschek.) 



may then be extended to a 



len retracted it lies within an enclosing muscular sheath. 



FlG. 172. Planar ia. Nervous system. 

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

 dinal nerve ; ph. pharynx. (After 

 Jijima and Hatschek.) 



relatively considerable distance. 



The 



