206 THE HAUNTS OF LIFE 



shore, for the conditions of life are more than 

 half terrestrial when the tide is out. 



In his fine introduction to Zoology, called 

 Animal Life, Professor F. W. Gamble gives a 

 vivid picture of the four chief kinds of animal 

 locomotion. He takes the case of a man in a 

 boat on a river, who can make headway against 

 the current in four ways, (i) He may take a 

 boat-hook and, fastening it to the roots on the 



FIG. 22. A JERBOA. 

 A leaping Biped belonging to the Rodent Order. 



bank, pull himself forward. So does a star-fish 

 pull itself up a rock ; so does a leech pull itself 

 forward when it fixes its mouth. This is the 

 pulling method. (2) He may take a pole, or 

 an oar for that matter, and, pressing it against 

 the bed of the stream, lever himself forward. 

 So does the beetle push its legs against the 

 ground ; so does the crab on the shore lever 



