42 



THE CHAIN OF LIFE. 



without being replaced by others. In so far as the areas of 

 the continents and the adjacent waters are concerned, those 

 periods when the land was subsiding under the ocean must 

 have been their times of prosperity, those in which the crust 

 of the earth shrunk and raised up large areas of land must 

 have been their times of decay. Still this lowest form of animal 

 life has never perished, but has always found abundant place 

 for itself, however pressed by physical change and by the 

 introduction of higher beings. 



