136 



CROCODILES AND ALLIGATOBS. 



in front of the internal nostrils, by means of a fold of 

 skin, thus leaving a free communication between the 

 nostrils and the wind-pipe. The advantage of this 

 arrangement to animals which, like crocodiles and 

 alligators, kill their prey by holding them under water, is 

 self-apparent. 



FIG. 45. Lower view (A) of Skull without the lower 

 jaw, and (B) upper view of Skull with lower jaw of 

 a Crocodile. O, orbit ; T, temporal pit ; P, palatal 

 vacuity ; N, internal nostrils. 



If to these differences between the skulls and teeth of 

 crocodiles and lizards, we add that, whereas in the latter 

 the ribs articulate to the joints of the back- bone or 

 vertebrae by means of little knobs on the sides of the 

 vertebrae themselves, in crocodiles they join the summits 

 of long horizontal processes of bone projecting from the 

 upper part of these vertebrae, we think we shall have said 

 enough to convince our readers that it is altogether in- 

 correct to speak of crocodiles and alligators as lizards. 

 Crocodiles are, indeed, first cousins of those extinct 



