TnK ki:PTii.i. Hook 



HEAD OF RATTLESNAKE 

 WTien the jaws are closed the fangs fold back against the roof of the mouth. They 

 are exactly like the hypodermic nt-edle — having an elongated orifice at their tip for 

 the ejection of venom. The opening near the front of the lower jaw shows the location 

 of the tongue-sheath. Thus it should be understood that the forked tongue is not a 

 sting or in any way connected with tlie poison apparatus 



SKLTLL OF A PIT \TPER, SHOWING DE\T,LOPING FANGS 



The illustration shows how fangs are constantly developing to take the place of the functional pair 



