Beaks and Bills 



225 



reaching about, or for proo^ressioii bein^ underslood. Bui 

 no one would think of alludino; to a bird's lips or nose; l)oth 

 are included in the terms beak, or l)ill, and nostrils. 



The finding and securing of food being the most im- 

 portant problem which birds have to solve for themselves, 

 it is for these purposes, and especially the last mentioned, 

 that we find bills most adapted. This is so universally 



Fio. l(v>.^BiII ()t Aniorican Raven. 



the case that we may often judge accurately of the kind 

 of food of a certain l)ir(l from a glance at its beak. 



As is the case with, so many other avian structures, 

 the horny, toothless beak or bill is duplicated elsewhere 

 in Nature only in a group of reptiles, tlie turtles and tor- 

 toises, whose mandibles furnish a splendid exanrple of 

 parallel evolution. 



In certain of those long-extinct Di7wsaurs, such as 



