174 



REPTILES AND BIRDS, 



genus Falco the bill is shorter than the head ; the upper mandible, 

 which is furnished at the base with a bare coloured skin, of a peculiar 

 dense texture, called the cere, in outline is slightly convex as far 



Fig. 60. Bill of Eagle. 



as the edge of the cere (Fig. 60), then curved so as to form about 

 the third of a circle, and is evidently destined, in connection with 

 its formidable claws, to tear its prey. 



Fig. 6 1. Bill of Toucan. 



In the Toucans (Ramphastida) the bill is half a foot long, hollow 

 within, thin, and nearly transparent ; and the mandibles are so dis- 

 posed as to combine, with their great bulk, strength and lightness, 

 and assist by their digestive power to assimilate both animal and 



Fig. 62. Bill of Cormorant. 



vegetable food (Fig. 61). In the Pelicanidse, as in the Common 

 Cormorant, the bill is long, straight, and compound ; the upper 

 mandible curved towards the point, the lower compressed; the 

 base inserted in a small membrane which extends under the throat. 

 In the back part of the head is an additional bone (Fig 62, a\ 



