INTRODUCTION. 25 



conical, about as broad as high at the Ibase, compressed to- 

 ward the end, and acute ; its upper mandible with its upper 

 or dorsal line nearly straight, the ridge broad and convex, 

 as are the sides, the edges inflected or bent inward, the notch 

 obsolete or very slight, the lower mandible with the angle 

 semicircular, the dorsal line straight, the back and sides con- 

 vex, the edges inflected. 



The bill of a Crow, Fig. 5, is rather long, straight, stout, 



Fig. 5. 



tapering, of nearly equal height and breadth at the base, but 

 compressed toward the end ; its upper mandible has the dor- 

 sal outline slightly arched, towards the end l>ent downwards, 

 the ridge rather narrow, the edges direct, that is, perpen- 

 dicular, neither bent outwards nor inwards, and having a 

 slight notch near the tip, which projects a little beyond the 

 other, and is bent a little downwards ; the lower mandible 

 has the angle of moderate length and width, the dorsal line 

 a little convex, the tip rather sharp. 



There can be no difficulty in understanding circumstances 

 so simple as these. In considering the bill attention is also 

 to be paid to the line formed by the two mandibles at their 

 meeting. This, the gape-line, may be straight, or arched, 

 or variously bent. 



The Tarsus varies in length and thickness, and may be 



