Organs of Nutrition 127 



a forward or backward direction. Along the sides of the 

 tongue are two series of fleshy teeth, in shape exactly 

 like the poison-fangs of a rattlesnake. 



Mention must be made of the unique and greatly 

 specialized tongues of Hummingbirds and Honey Creepers. 

 The outer edges of this organ are curled into two tubes, 



Fig. 100. — Side view of Flamingo's tongue, forcibly lifted above mandible, show- 

 ing fleshy recurved teeth. 



which are more or less split and frayed near the tip, 

 forming delicate brushes — efficient instruments either to 

 suck up nectar or to flick out insects from the heart of 

 corollas^'^ 



The Crop 



From the back of the throat to the stomach extends 

 a tube, the gullet or oesophagus, through which the food 



