INTRODUCTION. 
25 
conical, about as broad as high at the base, compressed to- 
ward the end, and acute ; its upper mandible with its upper 
or dorsal line nearly straight, the ridge broad and conyex, 
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 bent 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 ga'pe-line, may be straight, or arched, 
or variously bent. 
The Tarsus varies in length and thickness, and may be 
