88 CORAL-REEFS. 



by MM. Quoy and Gaimard, whether any kind of coral can 

 even withgtand, much less flourish in, the breakers of an 

 open sea: 1 they affirm that the saxigenous lithophytes 

 flourish only where the water is tranquil, and the heat 

 intense. This statement has passed from one geological 

 work to another ; nevertheless, the protection of the whole 

 reef undoubtedly is due to those kinds of coral, which cannot 

 exist in the situations thought by these naturalists to be 

 most favourable to them. For should the outer and living 

 margin perish, of any one of the many low coral-islands, 

 round which a line of great breakers is incessantly foaming, 

 the whole, it is scarcely possible to doubt, would be washed 

 away and destroyed, in less than half a century. But the 

 vital energies of the corals conquer the mechanical power 

 of the waves ; and the large fragments of reef torn up by 

 every storm, are replaced by the slow but steady growth of 

 the innumerable polypifers, which form the living zone on 

 its outer edge. 



From these facts, it is certain, that the strongest and most 

 massive corals flourish, where most exposed. The less per- 

 fect state of the reef of most atolls on the leeward and less 

 exposed side, compared with its state to windward; and 

 the analogous case of the greater number of breaches on 

 the near sides of those atolls in the Maldiva Archipelago, 

 which afford some protection to each other, are obviously 

 explained by this circumstance. If the question had been, 

 under what conditions the greater number of species of 

 coral, not regarding their bulk and strength, were developed, 

 I should answer, — probably in the situations described by 

 MM. Quoy and Gaimard, where the water is tranquil and 



1 Annates des Sciences Naturelles^ tome vi. pp. 276, 278. — " La oil 

 les ondes sont agitees, les Lytophytes ne peuvent travailler, parce 

 qu'elles detruiraient leurs fragiles edifices," etc. 





