96 



NATURE S TEACHINGS. 



common rat-trap, or gin, such as is sold for eightpence, with 

 the jaws wide open, so as to show the teeth. On the left is a 



JAWS OF DOLPHIN (OPEN). 



RAT-TBAP (OPEN). 



sketch of the upper and lower jaws of the Dolphin, in which 

 an exactly analogous structure is to be seen. 



The figure on the right hand of the lower illustration shows 

 a man-trap as it appears when closed, the teeth interlocking so 

 as exactly to fit between each other. The same principle is 

 exhibited in the jaws of the Porpoise, which are seen on the left 

 of the illustration. The jaws of an Alligator or Crocodile would 

 have answered the purpose quite as well, inasmuch as their 



JAWS OF PORPOISE (CLOSED). 



MAN-TRAP (CLOSED). 



teeth interlock in a similar fashion, but I thought that it would 

 be better to give as examples the jaws of allied animals. The 

 reason for this interlocking is evident. All these creatures feed 

 principally on fish, and this mode of constructing the jaws 

 enables them to secure their prey when once seized. 



Another example of such teeth is to be found in the fore-legs 

 of various species of Phasma and Mantis, as may be seen by 



FORE-LEGS OF PHASMA. 



MOUSE-TRAP. 



reference to the illustration. The latter insects are wonderfully 

 fierce and pugnacious, fighting with each other on the least 

 provocation, and feeding mostly on other insects, which they 



