CORAL POLYPS. 



13 



islands and continents, the abode of the human race, 

 is no less worthy of attention. The two tiny creatures 

 — one almost microscopic in size, the foraminifera. 



Coral polyp, open and oloaed. 



and the other not very 



much larger, the coral 



polyps — are the most 



important of all the 



home makers among the lower animals, for without 



them man nor beast could scarce have found rest for 



the soles of their feet. 



The coral animal begins life as a free-swimming, lit- 

 tle worm-like creature, called & planula. It is covered 

 with cilia or bristles, which by their continual motion 

 act as paddles or oars, and enable the planula to pro- 

 gress through the water. After a time the creature set- 

 tles down, and, fastening itself to a rock or a piece of 

 dead coral by its larger end, begins to live like a vege- 

 table rather than an animal, having lost the power of 



