294 



REPTILES. 



FIG. 318. BOA CONSTRICTOR WATCH INC; FOR PREY. 



throat and jaws, being in an extreme state of tension, would force out of the mouth 

 what had alr.eady been partially swallowed. To provide against this, the teeth are, by 

 their position, converted into a sort of valve. Pointing backwards as they do, they 

 permit the bulky food to pass down towards the throat, but at the same time their sharp 

 points efficiently prevent it from being pushed back again in the opposite direction : 



"facilis descensus Averni 



Sed revocare gradum, superas que evadere ad auras. 

 Hoc opus hie labor est." 



The largest of all the Boa family, and perhaps the largest of the Serpent 

 race, is 



The Anaconda (Euncdcs mitrinus}, found only on the American cont ; nent. It 

 is to this species that we must refer the greater number of the highly-exaggerated tales 



