Organs of Nutrition 121 



fringed to correspond with the serrated or otherwise 

 indented edges of the mandibles. One which is before me 

 as I write is very elaborate. It is that of a wild Mallard 

 Duck. At the tip is a thin, distinct flap or lamella, horny 

 and with smooth edges. Behind it the tongue enlarges 

 abruptly into a thick oblong mass, deeply grooved down 



Fig. 92.-Bill of Jirown Pelican showing extreme reduction of tongue in a bird 

 which swallows whole fish. 



the center. The edges of the anterior half are fringed 

 with a double line of horny hairs, while in the posterior 

 portion the upper hne is replaced with tooth-like struc- 

 tures. The upper surface is smooth in front, but farther 

 back two central folds arise and curve over laterally, 

 forming tube-like grooves. Still more posteriorly, fleshy 

 recurved teeth are visible, singly, in groups, or in regular 

 lines. The tongue of our con:mou barnyard duck is 



