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VERTEBRATES 



The Crocodile is an inhabitant of the Old World, the 

 Alligator of the New, and the two animals are best distinguished 

 by the construction of the jaws. In the Crocodiles the lower 

 canine teeth fit into a Tiotch in the edge of the upper jaw, and 

 there is in consequence a contraction of the muzzle just behind 

 the nostrils. The lower canine teeth of the Alligators fit into a 

 2nt in the edge of the upper jaw, and in consequence no contrac- 

 tion is needed. At the hack of the throat is a valve completely 

 shutting out water, but leaving the passage to the nostrils free, so 



The Crocodile. 



•fiat the Crocodile can keep his mouth open when beneath the 

 surface, without swallowing the water, or can hold his prey to 

 drown under the water while he himself breathes at ease with his 

 nostrils at thejurface. There is no true tongue. 



The Crocodile lays eggs of the size of those of a goose, to 

 the number of about sixty, which she covers over with sand, 

 leaving them, like the ostrich, to be hatched by the heat of the 

 sun. They are to be met with in the rivers Nile, Niger, and 

 Ganges, and in many other large rivers in the southern parts of 



