78 



CORAL AND ATOLLS 



Althongli a very large number of corals have the normal 

 habit of reproducing equally from all parts of their surface, 

 still evidences may be seen, at many points of most colonies. 



Fig. 16. 



Vegetative Reproduction in Corals. 



a. Type in which the daughter zooids become completely separated. 

 I. Type in which separation of the daughter zooids is less complete. 



that certain groups of zooids are more active than their 

 fellows. 



The special activity of these zooids may be due to purely 

 local causes ; it may be called forth merely by irritation of a 



FiCx. 17. 



Vegetative Reproduction in Corals, 



a. Further stage of incom{)lete separation of zooids 



b. Meaiidrine type of division. 



localised portion of the surface of the colony ; or it may be 

 a real alteration of vegetative habit. It is an outstanding 

 fact m all the colonies observed for long intervals that the 



