THE CONQUEST OF THE DRY LAND 207 



does the crab on the shore lever itself along; 

 so do we when we walk. This is the punting 

 method. (3) He may take an oar, and, going 

 to the stern of the boat, he may press the water 

 from side to side, displacing masses of water 

 in a regular rhythm. So does the fish grip the 

 water with the posterior part of its body, popu- 

 larly called the tail, and thrust the water away 

 from it, first to one side and then to the other. 

 So does the whale with its propeller-like tail 

 a propeller, however, that does not go round. 

 This is the sculling method. (4) Or the man 

 may sit down on the seat of the boat and take 

 up the oars and row. The insect called the 

 Water-Boatman rows on the water with its third 

 pair of legs; the turtle rows with its flipper- 

 like limbs, and the penguin with its flightless 

 wings and with its feet as well. Aquatic birds, 

 when swimming, row with their feet; some 

 diving birds row under water with their wings. 

 Flying birds row in the air with their wings. 



Now it may be said that the conquest of the 

 dry land meant, among other things, that the 

 punting kind of locomotion became very im- 

 portant. It was learned on the shore; it was 

 perfected on dry land. Even the snake, which 



