472 



A CORAL REEF. 



The examination of a coral reef during the different 

 stages of the -tide is, as Captain Hall says,* particularly 

 interesting. When the sea has left it for some time, it 

 becomes dry, and appears as a compact rock, exceedingly 

 hard and rugged ; but no sooner does the tide rise again, 

 and the waves begin to wash over it, than millions of 

 coral-worms protrude themselves from apertures on the 



THE FAN GORGON 



surface which before were quite invisible. These animals 

 are, as we have shown, of various shapes and sizes, and 

 so prodigious in number, that in a short time the whole 

 face of the rock seems alive and in motion. The most 

 common form is that of a star, with arms, or rays, from 

 four to six inches in length, which the animal moves 



* Captain Hall, "Voyage to the Loo-Choo Islands." 



