134 



TETRAO. GROUSE. 



Bill short and strong, slightly curs'ed ; upper mandible hav- 

 ing its dorsal outline nearly straight at the base, towards the 

 end arcuato-declinate, the ridge broad and convex, the sides 

 convex towards the end, the edges nearly straight, and ascend- 

 ing to beyond the nostrils, then declinate, sharp, and over- 

 lapping, the tip rounded and thin-edged ; lower mandible 

 with its angle broad and rounded, the dorsal outline slightly 

 convex, the back broad, the sides convex, the edges arched, 

 thin, erect, the tip rounded. 



Mouth narrow ; upper mandible concave internally, with a 

 prominent central ridge ; lower mandible concave, with a 

 broad central gi'oove, and two prominent lines. Palate flat, 

 with two slightly papillate soft ridges, from which a papillate 

 flap proceeds to the middle of the nasal aperture, and another 

 curves behind it. Aperture of the posterior nares oblong be- 

 hind, anteriorly linear, its edges papillate ; the anterior space, 

 defined by the soft ridges, covered with pointed papillae in trans- 

 verse series, the posterior space sj^arsely covered with smaller 

 papillae. Tongue short, triangular, flat above, papillate at the 

 base, horny beneath at the end, acute. Two masses of mucous 

 crypts in the angle of the lower jaw ; also a series on the low^er 

 side of the tongue on each side, and a great quantity in the 

 space between the root of the tongue and the aperture of the 

 glottis. The latter is defended behind by two transverse flaps 

 of pointed papillae. 



G^sophagus narrow at its two extremities, enlarged into a 

 crop of great size, lying over the forepart of the neck and 

 thorax. In its whole extent it is abundantly supplied with 

 mucous follicles, as is the crop for a short space around its 



