32 
DUSKY GROUS. 
The genus Tetrao is now composed of thirteen species, three 
Lagopodes, two Bonasise, and eight typical Tetraones. This enume¬ 
ration does not include the Tetrao rupestris, which we do not 
consider well established, any more than the new species of Mr. 
Brehm. The species of Lagopus, as might be inferred from their 
inhabiting high northern latitudes, are common to both continents, 
with the exception of the Red Grous, T. scoticus, which is peculiar 
to the British islands, and which, from its not changing the 
colours of its plumage with the seasons, may be considered as 
forming the passage to the true Tetraones. Of these there are five 
in North America, each and all distinct from the three European. 
Of the two Bonasise, one is peculiar to the old, and the other to 
the new continent, the former having sixteen, the latter eighteen 
feathers to the tail. Thus the entire number is seven in Europe, 
while it is eight in North America. Setting aside the two common 
to both, and the respective Bonasise, we may consider the Cock of 
the Woods of Europe, as the parallel of the Cock of the Plains of 
America. The Black Grous, T. tetrix, will find its equivalent 
in the Dusky Grous, T. obscurus; but the T. hybridus has no 
representative in America, any more than the T. scoticus. These 
however are more than replaced as to number, by the T. 
phasianellus, T. cupido, and T. canadensis, all American species 
which have none corresponding to them in the old world. 
Perhaps no other naturalist has personally inspected all the 
known species of this genus of both continents, and having 
examined numerous specimens even of some of the rarest, and 
possessing all but one in my own collection, my advantages are 
peculiar for giving a monography of this interesting genus. Such a 
work it is my intention hereafter to publish, illustrated with the 
best figures, and accompanied with further details respecting their 
habits. In the mean time I shall merely state, that being replaced 
in Africa by Pterocles, and in South America by Tinamus, all the 
