24 INTRODUCTION. 



upper mandible having its upper outline convex from the 

 base, the sides convex, the edges with a festoon about the 

 middle, and toward the fore part an angular toothlike projec- 

 tion, the tip curved downwards, three-cornered, and sharp ; 

 the lower mandible with the angle or meeting of its crura 

 wide and rounded, its lower outline very convex, the edges 

 involute, or curved inwards, and having a rounded notch 

 near the tip, which is truncate, or as if cut off abruptly. 

 The bill of a Swallow, Fig. 3, is very short, much de- 



Fig. 3. 



pressed, that is, flattened, or as if pressed downwards, and of 

 a triangular form ; its upper mandible with its upper or dor- 

 sal outline sloping but convex, the edges slightly inflected, 

 or bent inwards, with a distinct notch, close to the tip, which 

 is slender, but blunt ; the lower mandible with the angle very 

 wide, the dorsal outline a little convex, the tip rather sharp. 

 Again, the bill of a Chaffinch, Fig. 4, is short, straight. 



Fig. 4. 



