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THE POPULAR SCIENCE MONTHLY 



Termite's Xest, Prince of Wales Island, Torres Straits. 



We saw that there is evidence of a struggle for existence between 

 the various kinds of corals, and according to Darwin's theory, we would 

 expect this to have improved the corals. The Australian forms must 

 withstand a very high temperature during the calm, hot days of the 

 "northwest" season, while those of Florida must suffer annually from 

 cold " northers." Yet, our experiments show that the Australian corals 

 are quite as sensitive to high temperature as are those of Florida, and 

 conversely the Florida corals can not withstand cold any better than can 

 those of tropical Australia. In other words, natural selection has not 

 improved the heat-resisting or cold-withstanding powers of the corals 

 and yet temperature is a factor of primary importance in determining 

 the life or death of reef corals. Of late years we have been steadily 

 losing respect for the efficacy of natural selection as a means of devel- 

 oping morphological or physiological adjustments. 



We must conclude that "corals are corals," and their behavior is 

 essentially alike both in Florida and in Australia. 



