LIFE-PROCESSES OF CORAL COLONY 117 



forsaking tbe growtli-forni of tlie colony, builds its repair in 

 the form best suited to the new conditions of the environment. 

 This is a strange zoological fact, that the inherent growth- 

 form, once stamped upon a well-established colony, continues 

 to be the type of growth, though it be but ill adapted to its 



Fig. 42. 



Moidipora Colony 

 Repairing a branching growth by an encrusting layer. 



habitat ; and yet, when the continuity is once broken and a 

 new start is made, the newly budded zooids can throw off the 

 stereotyped method, and build anew to the altered conditions. 

 It is facts such as these which give some clue to the under- 

 standing of the vast range of variation occurring within the 

 limits of a species, and make the establishing of a species a 

 matter of extreme doubt, until every possible variation which 

 different surroundings will stamp upon the type has been 

 examined. We have seen, in following the life-history of 

 corals, that the colony shows great adaptability, being able to 



