178 AGE OF CORAL EEEFS. 



init and the sides with their delicate, graceful 

 forms. Such an intricate underbrush of Coral 

 growth affords an excellent retreat for many 

 animals that like its protection better than ex- 

 posure to the open sea, just as many land-animals 

 prefer the close and shaded woods to the open 

 plain. A forest is not more thickly peopled with 

 Birds, Squirrels, Martens, and the like, than is 

 the Coral Reef with a variety of animals which 

 do not contribute in any way to its growth, but 

 find shelter in its crevices, or in its near neigh- 

 borhood. 



But these larger animals are not the only ones 

 that haunt the forest. There is a host of parasites 

 besides, principally Insects and their larvae, which 

 bore their way into the very heart of the tree, 

 making their home in the bark and pith, and not 

 the less numerous because hidden from sight. 

 These also have their counterparts in the Reef, 

 where numbers of boring Shells and marine 

 Worms work their way into the solid substance 

 of the wall, piercing it with holes in every direc- 

 tion, till large portions become insecure, and the 

 next storm suffices to break off the fragments so 

 loosened. Once detached, they are tossed about 

 in the water, crumbled into Coral sand, crushed, 

 often ground to powder by the friction of the 

 rocks and the constant action of the sea. 



After a time, an immense quantity of such 



