LIFE-PROCESSES OF CORAL COLONY 105 



biological fact that the actinozooid is a living thing which knows 

 no time of youthful vigour, no waxing to a period of adult 

 life, no waning to senility — it knows no age — it practically 

 knows no natural death. There is no building on the dead 

 bodies of ancestors, no perpetual dying and new birth. A 

 colony of Madrepora will contradict this popular fallacy at 

 one glance, for, whatever the age of the growth, the parent 

 anthozooid flourishes till death or accident overtakes the 

 whole. It is a wonderful thing — and one which is not, I think, 

 generally considered — that the age of some of these indi- 

 viduals in every colony must be excessive, even reckoned as 

 Ave reckon the age of higher animals. When we consider the 

 very slow rate of growth of some corals, and the great size of 

 some of the colonies to be seen every day on an atoll reef, 

 and when we rightly understand their mode of growth, and 

 recognise that the pioneer organism of the colony is still 

 flourishing there, we cannot help being struck by the excessive 

 antiquity of that organism as a living entity. That an apical 

 zooid of a branching Madrejjora colony should be ten years 

 old seems wonderful, but these individuals are mere juveniles 

 when some cf the component zooids of massive growths are 

 considered. 



Throughout the prolonged life of these lowly animals the 

 process of repair is a possibility, and a strange paradox is 

 presented in some forms, for the most aged member of the 

 colony shows the greatest activity in all the processes of 

 renewal and repair. 



The coral colony increases in size by the budding-off of nevv 

 zooids and the deposition of new calcium carbonate in their 

 tissues, and just as this is the ordinary mode of growth, so it 

 is the ordinary mode of repair. The type of repair naturally 

 tends to follow the type of growth of the injured colony ; and 

 the various genera of corals might be taken in order and the 

 details of the repair of injury noted for each genus. But it is 

 more likely that some idea of the bionomics of the group 

 will be gathered from the general study of the phenomena 

 as they aftect the life-history of the coral than from a survey 



