86 
CONDITIONS FAVOURABLE TO 
Cn. IV. 
strongest corals live on the outer reefs, and appear to 
love the surf ; he adds, that the more branched kinds 
abound a little way within, but that these in still 
more protected places become smaller. Many other 
facts having a similar tendency might be adduced . 1 It 
has, however, been doubted by MM. Quoyand Gaimard, 
whether any kind of coral can even withstand, much 
less flourish in, the breakers of an open sea ; 2 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 
is undoubtedly due to those kinds of coral, which 
cannot even 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. 
1 In the West Indies, as I am informed by Captain Bird Allen, 
R.N., it is the common belief of those who are best acquainted with 
the reefs, that the coral flourishes most where freely exposed to the 
swell of the open sea. 
2 Annales des Sciences Naturelles, tom. vi. pp. 27G, 278. — 1 La ou 
les ondes sont agitdes, les Lytophytes ne peuvent travailler, parce 
qu’elles detruiraient leurs fragiles Edifices,’ &c. 
