The Story of Evolution 83 



It is not an easy haunt of life, but none the worse for 

 that, and it is tenanted to-day by representatives of practically 

 every class of animals from infusorians to sea-shore birds and 

 mammals. 



The Cradle of the Open Sea 



2. The open-sea or pelagic haunt includes all the brightly 

 illumined surface waters beyond the shallow water of the shore 

 area. 



It is perhaps the easiest of all the haunts of life, for there 

 is no crowding, there is considerable uniformity, and an abun- 

 dance of food for animals is afforded by the inexhaustible 

 floating "sea-meadows" of microscopic Algae. These are reincar- 

 nated in minute animals like the open-sea crustaceans, which 

 again are utilised by fishes, these in turn making life possible for 

 higher forms like carnivorous turtles and toothed whales. It is 

 quite possible that the open sea was the original cradle of life 

 and perhaps Professor Church is right in picturing a long period 

 of pelagic life before there was any sufficiently shallow water to 

 allow the floating plants to anchor. It is rather in favour of this 

 view that many shore animals such as crabs and starfishes, spend 

 their youthful stages in the relatively safe cradle of the open sea, 

 and only return to the more strenuous conditions of their birth- 

 place after they have gained considerable strength of body. It 

 is probably safe to say that the honour of being the original 

 cradle of life lies between the shore of the sea and the open 

 sea. 



The Great Deeps 



3. A third haunt of life is the floor of the Deep Sea, the 

 abyssal area, which occupies more than a half of the surface of the 

 globe. It is a region of extreme cold an eternal winter ; of utter 

 darkness an eternal night relieved only by the fitful gleams of 

 "phosphorescent" animals; of enormous pressure 2 l /2 tons on 



