DUSKY GROUSE. 375 
perhaps superior to all others in these respects since the dis- 
covery of the cock of the plains. Although the careful and 
accurate researches of Wilson had led him to the belief that 
there existed but two species of grouse in the territory of the 
United States, no less than six are now known to inhabit 
within their boundaries. But we are not aware that any of the 
subgenus Lagopus ever enters the confines of the Union, not- 
withstanding the pains we have taken to obtain information 
on this point from the high northern districts of Maine and 
Michigan, in which, if anywhere, they are most likely to be 
discovered. It would, however, be very extraordinary if these 
birds, which are found in the Alps of Switzerland, should not 
also inhabit the lofty ranges of the Rocky Mountains, which 
are known to be the resort of the various species of grouse. 
With the exception, therefore, of the well-known Tetrao wm- 
bellus, which belongs to Bonasza, all the others are true grouse, 
Tetraones. 
The spotted and the sharp-tailed grouse were lone since 
known as inhabitants of that part of America north of the 
United States, but the two others are newly added, not only 
to our fauna, but to the general system, being found for the 
first time in the American territory, and not elsewhere. For 
the history of the discovery, the manners, habitation, and a 
particular description of each of these, we shall refer the reader 
to their several articles. 
The dusky grouse is eminently distinguished from all other 
known species by having the tail slightly rounded, and com- 
posed of twenty broad and rounded feathers. This peculi- 
arity of the extraordinary number of tail-feathers is only found 
besides in the cock of the plains, in which, however, they are 
not rounded, but very slender, tapering, and acute. In size 
and colour, the dusky grouse may be compared to the black 
grouse of Kurope, so remarkable for the outward curvature 
of the lateral feathers of the tail. 
The figure in our plate is taken from the specimen on which 
Say established the species ; this was killed on a mountain in 
