FALCONING. AQUILA. 39 



late brown, the forehead and base of the tail white, the lat- 

 ter barred with white and brown. 



Male, 21, 51, 17, ly 4 ^ 2, 1 T 3 5 , . Female, 23, 56. 



Easily distinguished, being the only British Falconine 

 Bird, except the Golden Eagle, that has the tarsi feathered. 

 It exhibits great variation in the tints of the plumage. Black 

 or dark brown individuals, occasionally seen in America, and 

 supposed to be adult or old, have never been observed with 

 us ; but one, shot in Dumfriesshire in March 1840, had a 

 great number of young feathers of a blackish-brown colour, 

 and would have been entirely of that tint, had the moult been 

 completed. A winter visitant in Britain and Ireland. 



Rough-legged Falcon. 



Falco lagopus, Gmel. Syst. Nat. i. 260. Falco lagopus, 

 Temm. Man. d'Ornith. i. 65 ; iii. 37. Buteo lagopus, Bough- 

 legged Buzzard, MacGillivray, Brit. Birds, iii. 193, 736. 



GENUS III. AQUILA. EAGLE. 



Bill shorter than the head, very high, gradually com- 

 pressed from the base ; upper mandible with the dorsal line 

 nearly straight along the cere, the ridge broad and convex, 

 the edges with a slight festoon, the tip prolonged, decurved, 

 trigonal, acute ; lower mandible with the angle of moderate 

 width and rounded, the dorsal line convex, as are the sides, 

 the tip rounded. Mouth wide ; tongue fleshy, deeply emar- 

 ginate and papillate at the base ; concave above, with the 

 sides nearly parallel, the tip rounded ; oesophagus very 

 wide, dilated into a large crop ; stomach large, roundish, its 

 muscular coat thin, the epithelium soft ; intestine rather 

 short, of moderate width, the duodenum forming a single 

 loop ; caeca very small ; cloaca very large and globular. 

 Nostrils broadly elliptical, oblique. Eyes large, with a 

 broad projecting superciliary ridge. External aperture of 

 ear large, roundish. Head large, roundish, flattened above ; 

 neck rather short ; body very robust. Feet of moderate 

 length, very stout ; tarsus very short, thick, feathered to the 

 tarso-digital joint ; toes of moderate length, stout, the first 

 and second shortest and thickest, the third next in length, 

 but the most slender, and connected with the fourth by a 

 pretty large web, all scutellate toward the end ; claws strong, 

 curved, tapering, laterally flattened, concave beneath, very 



