THE SEA 21 



the polar regions to sink and move slowly toward 

 the tropics, replacing the warmer surface water of 

 the tropics, which flows toward the poles. 



In the future, greater knowledge concerning the 

 ocean currents ought to enable the "weather man" 

 to predict average seasonal temperatures months in 

 advance. We might also be able to predict the dis- 

 tribution of icebergs in the North Atlantic and 

 perhaps the prospects of the marine fisheries. 



Life in the Sea 



When we collect all of the evidence of the evolu- 

 tionary development of plants and animals found by 

 biologists and place it side by side with the facts 

 revealed to us by geology and oceanography, the 

 irresistible conclusion is reached that the sea was the 

 cradle of life upon the earth and that all plants and 

 animals were originally derived from ancestors that 

 lived in the sea. Curiously enough, the salts found in 

 sea-water are found in human blood-plasma in almost 

 exactly the same proportions. This physiological 

 fact seems to. confirm the biological evidence tending 

 to prove that man has evolved from simpler marine 

 animal organisms. 



It is also interesting to note that the depths of 

 the sea have revealed a few survivors of earlier 

 geological periods whose histories are written in 

 stone. Crinoids, or sea-lilies, have existed since early 

 geologic times and are still found in the sea; one 

 important bed of these curious animals has been 

 discovered off the coa^t of Cuba. Yes, sea-lilies are 



