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FAMILY XXXIL— TETRAONIN^. GROUSE. 



Bill short, stout, with the upper mandible convex, thin edged, without 

 notches, its tip thin edged, obtuse, the lower mandible with the dorsal line 

 slightly convex, the edges thin, the tip rounded. Head small, oblong; neck 

 of moderate length; body very bulky. Feet short, stout; tarsus partially 

 or entirely feathered; hind toe small, third long, lateral nearly equal, all 

 scutellate, anterior webbed at the base. Claws moderate or long, arched, 

 rather depressed, blunt. Plumage full and soft; feathers with the plumule 

 much developed. Wings rather short, convex, rounded. Tail various, of 

 more than twelve feathers. A bare coloured space on each side of the neck, 

 usually concealed by the feathers; but in some species capable of being 

 distended so as to protrude. A bare red membrane over the eye, more 

 developed in the males. Tongue triangular, pointed; oesophagus with an 

 enormous crop; stomach a very powerful gizzard, having the lateral muscles 

 extremely developed, the epithelium dense, with two concave grinding 

 surfaces; the intenstine long and wide; cceca excessively elongated, cylin- 

 drical, with internal longitudinal ridges. Nest on the ground, rudely 

 constructed. Eggs numerous, spotted. Young covered with stiffish down. 



Genus I.— TETRAO, Linn. GROUSE. 



Bill short, robust; upper mandible with the dorsal line decurved, the 

 ridge convex, narrowed at the base, the sides convex, the edges sharp and 

 overlapping, the tip thin-edged and rounded; lower mandible with the angle 

 long and wide, the dorsal line convex, the sides rounded, the edges inflected, 

 the tip rounded. Nostrils roundish, in the fore part of the large and 

 feathered nasal depression. Head small, ovate; neck of ordinary length; 

 body large and full. Feet stout, of moderate length; tarsus short, feathered, 

 at the lower part sometimes bare and scutellate; toes bare, scutellate, with a 

 marginal fringe of pectinate scales. Claws rather large, arched, compressed, 

 obtuse. Plumage full, soft, rather blended. Wings rather short, convex, 

 much rounded, the third and fourth quills longest. Tail rounded, of more 

 than twelve feathers. 



