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TEXT-BOOK OF ZOOLOGY 



deeply cleft and protrusible to a considerable distance ; at its base it is 

 enclosed within a sheath. It can be protruded even when the mouth is 

 closed, through a notch at the tip of the snout. There is no trace of 

 external ears, and the hearing is dull. 



RINGED SNAKES. 



(About one-sixth natural size.) 



The animal on the bank is depicted in the act of 



2. The snake captures its prey by stealthily 

 creeping up to it, or lying in wait for it, and then 

 rapidly darting forward and seizing it in its 

 mouth. It is fond of the water, and is an excel- 

 lent swimmer and diver. 



8. Being limbless, the snake cannot hold its 

 prey and tear it gradually to pieces, but has to 

 swallow it whole, and, indeed, before it is actually 

 killed (compare, on the other hand, the viper). 



4. How, then, does a snake manage to swallow '" -X- ^ 



a large frog, which is thicker than its own body, 



and especially than its slender head ? For this operation provision is 

 made as follows : 



(a) The gape of the mouth is very ivide (give the situation of the angles 

 of the mouth). 



