104 CORAL AND ATOLLS 



maximum power of repair of damage, or regeneration of 

 lost parts ; and in the colonial forms, which are of special 

 importance in the economy of the class, this power is greatly 

 intensified. 



In the group of solitary corals there is no very great 

 interest attached to the processes of repair. The individual 

 animal is at times damaged by injury, and the damage is 

 repaired by the laying down of new calcified material, causing 

 an irregularity in the symmetry of the animal. As a common 

 feature of repair in any living thing, it may be noticed that 

 the new material laid down tends to be excessive. Few 

 large Fungice are to be found in which some injury has not 

 caused the development of a quantity of irregular calcification 

 where the delicate tissues of the animal have been split over 

 the sharp edge of one of the rays. Excessive injury leads to 

 local death, and local death may affect a very large area of a 

 solitary coral without being necessarily fatal to the whole 

 animal. The individual has but little power of repairing 

 a large portion of its surface when once the area is definitely 

 dead — very often for the reason that parasitic algae and sponges 

 attack the dead area. 



It is not till the colonial forms are reached that the power 

 of repair possessed by the corals is properly seen. In a colony 

 composed of myriads of individuals each actively living, each 

 capable of growth and repair, the very best conditions for 

 repair are at hand, and this is further aided in many cases 

 by the peculiar mode of growth of the colony. There are 

 some inherent characteristics of the lowly animals amongst 

 which the corals rank zoologically that are very wonderful, 

 and which are opposed both to the order of things which pre- 

 vails in the higher classes, and also to the popular conception 

 of the life-history of the reef-building corals. 



I think it is fair to say that the average belief with 

 regard to the building of corals and coral-reefs is that the 

 zooids live and grow, flourish and die, and that their dead bodies 

 form mausoleums on which their progeny found their colony, 

 and thus build islands. Now in contradiction to this is the 



