20 THE HAUNTS OF LIFE 



are stormy days when the waves are literally 

 breakers. There are fresh-water floods from 

 inland, smothering masses of jetsam from the 

 sea, and clouds of wind-driven sand from the 

 beach and the dunes. In the polar regions 

 there are difficulties due to the ice; in the 

 equatorial regions there are difficulties due to 

 the scorching sun. 



Many problems are presented by the differ- 

 ences between tide in and tide out: animals 

 that have been bathed in water for many 

 hours are left high and dry. Let us look at 

 a few of the solutions. 



All animals require oxygen to keep the vital 

 processes agoing, for there is no living with- 

 out combustion. Oxygen is required to keep 

 the fire of life burning. Now marine animals 

 find the indispensable oxygen mixed with the 

 water, and seashore water, where there are 

 waves, is very rich in oxygen. But an animal 

 accustomed to use the oxygen mixed with the 

 water cannot suddenly change and become 

 able to use the oxygen mixed with the air. 

 This is one of the problems raised by the out- 

 going tide. 



The Purse Sponge (Grantla compressa) 



