DEATH-PROCESSES OF CORAL COLONY 127 



extent to which a colony of Milleporct comijlanata may be 

 riddled with the wide smooth-walled tubes, and yet not be 

 appreciably weakened, and the resultant observation on such 



Fia. 45. 



Specimen showinu the Tunnelling of a Living Coral 

 Colony by Boking Parasites. 



colonies is that the borings are very little harmful to the 

 colony. 



Another cause of coral death to which much importance 

 has been attached is the exposure caused by the receding tide, 

 for it has been said that corals cannot survive even a 

 temporary exposure to the sun and air. 



Since Darwin first claimed this as an axiom of coral 

 bionomics, a great deal has been taken for granted with regard 

 to the effects of exposure, and yet every fresh investigator 

 has attached less and less importance to it. Now, as a matter 



