GROUSE. 



207 



as to its appearance and habits, that it will be unnecessary to devote any space to it 

 here. Cuba possesses a species very similar in plumage, O. cubensis, differing mainly 

 in the greater extent of black upon the head and upper part of breast. A beautiful 

 species, 0. nigrogularis^ is a native of Honduras and Yucatan, having a black throat, 

 and a white breast and abdomen, the feathers of these being bordered with black. 

 The remaining species of the genus, three or four in number, are found in Mexico, one 

 only 0. leylandi, being a native of Honduras and Costa Rica. 



FIG. 97. Layopus albus, ptarmigan, in summer plumage. 



The grouse comprise the sub-family Tetraoninre of the Perdicida?, and are distin- 

 guished from the quails and partridges by having the nostrils, legs, and feet more or 

 less completely feathered, by a bare skin over the eye, a pectination on the sides of 

 the toes, and in some species by a bare distensible skin on the side of the neck. They 

 are confined generally to the northern districts of both hemispheres, but are most 

 numerous in North America. They are usually contained in eight genera, with one 

 or two sub-genera, and consist of about twenty-three or twenty-four species. 



The ptarmigan, comprising the genus Layopus, differ from the typical grouse by 

 having the toes as heavily feathered as are the tarsi, and also, with one exception, by 



