42 The Under-Water World 



termed a " polyp " " a creature with 

 many feet/' A polyp has a cylindrical 

 body, with one end attached to some 

 solid base such as a rock, and the other 

 the upper end, exposed to the world 

 at large. The latter takes the form of 

 a disc surrounded by tentacles, and 

 is often provided with stinging cells. 

 Through the mouth or upper end, which 

 passes direct into the hollow body, all 

 waste matter is ejected after being 

 digested. When a polyp is hungry it 

 expands, and spreading out its tentacles, 

 which may number several thousands, 

 flourishes them in the surrounding water 

 until it finds something which promises 

 a meal. An anemone has not the slight- 

 est vestige of a brain. Yet anyone 

 trying to feed the animal with stones 

 will find such fare will be steadily 

 rejected ; whilst if it is offered some- 

 thing more appetising -a piece of fish, 

 meat or shrimp such dainties will be 



