GROWTH OF THE CORAL COLON\^ 99 



pliysical conditions of its surroimdings are always alterino-. 

 The terms rough Avater and smooth water, deep or shallow, 



Fig. 33. 



The Influence of Environment on Coral Growth. 



Series of young colonies of Pocillopora in their position of growth 

 upon a floating log. 



and sedimenting or non-sedimenting, are therefore only 

 comparative ; for what to-day is a habitat free from sediment 

 may in the course of a few weeks become the site of a copious 

 deposition of silt. The rise and fall of the tide across the 



