REPTILES OPHIDIANS DIAGRAM 5 89 



black tongue now and then, which is bifurcated at the end, like 

 that of all lizards and serpents, but which cannot do any 

 injury. 



CROCODILES. The crocodiles are a kind of large lizard which 



inhabit the rivers of hot countries. 

 They sometimes grow to a consid- 

 erable size, and attain a length of 

 five or six yards. They have a 

 great number of pointed teeth, and 

 Head of Crocodile. are verv voracious. 



They live chiefly on fish. They come to bask in the sun on 

 the bank, and only move on land with difficulty ; but they 

 recover all their agility on the water, where they can dive for a 

 very considerable time. 



OPHIDIANS DIAGEAM 5. 



Ophidian is derived from the Greek word ophis, which means 

 serpent. There are in this country only two races of serpents, 

 one of Tvhich, the viper, is venomous, and the other, the common 

 snake, is not. The viper is the smaller ; it may be known at 

 once by its yellow colour, with a broad undulating black line 

 along the back. On the top of the head, this black line is 

 double, and forms a V. 



The viper only is venomous. On opening the mouth of a dead 

 viper, which must always be done with great caution, because 

 there is still some danger, we find, in addition to a number of 

 fine sharp teeth, two teeth much larger than the others. They 

 are situated on each side of the upper jaw, close against it, and 

 partly covered by a fold of skin. These teeth are called fangs, 

 and are not firmly fixed in the jaw like the others ; they lie 

 against the gum, or are raised at the wish of the animal, by a 



