106 NATURE'S TEACHINGS. 



the hand be inserted between the jaws, to get it out again 

 is almost impossible without assistance, and often has the 

 spectacle been exhibited of a youthful angler returning discon- 

 solately home, with his right hand in the mouth of a Pike, and 

 supporting the weight of the fish with his left. 



THE teeth of a serpent are set in a similar manner, as can be 

 seen by reference to the illustration on page 80. An admirable 

 example of the power of this arrangement may be seen in the 

 jaws of our common Grass or Ringed Snake (Coluber natrix), 

 The teeth are quite small, very short, and not thicker than fine 

 needle-points. Yet, when once the snake has seized one of the 

 hind-feet of a frog, all efforts to escape on the part of the latter 

 are useless. The lower jaw is pushed forward, and then re- 

 tracted, and at each movement the leg is drawn further into 

 the snake's mouth, until it reaches the junction. 



The snake then waits quietly until the frog tries to free 

 itself by pushing with its other foot against the snake's mouth. 

 That foot is then seized, the leg gradually following its com- 

 panion, and in this way the whole frog is drawn into the 

 interior of the snake. I have seen many frogs thus eaten, but 

 never knew one to escape after it had been once seized by the 

 snake. As these reptiles are perfectly harmless, it is easy to 

 try the experiment by putting the finger into a snake's 

 mouth, when it will be found that the assistance of the other 

 hand will be needful in order to extricate it. 



BELOW the head of the pike is a view of a Shark's jaws, as 

 seen from the front. 



Here, again, we have a similar arrangement of teeth, row 

 after row of which lie with their points directed towards the 

 throat of the fish. As, however, the pike and the snake 

 swallow their prey whole, their teeth need be nothing but 

 points. But, as the Shark is obliged to mangle its prey, and 

 seldom swallows it whole, its teeth are formed on a different 

 principle, each tooth being flat, wide, sharply pointed, and 

 having a double edge, each of which cuts like a razor. So knife- 

 like are they, indeed, that when a whale is killed, the sharks 

 which surround it bite off huge mouthfuls of blubber, and, as 

 they swarm by hundreds, cause no small loss to the whalers. 



