28 
DUSKY GROUS. 
winter plumage is an additional protection against rapacious 
animals, by rendering it difficult to distinguish them from the 
snows by which they are surrounded. II. Tetrao, which is 
distributed over the more temperate climates; the legs being 
still feathered down to the toes. III. Bonasia, a new division, 
of which we propose Tetrao bonasia , L. as the type, in which only 
the upper portion of the tarsus is feathered. These occasionally 
descend still farther south than the others, inhabiting wooded 
plains as well as mountainous regions, to which those of the 
second section are more particularly attached. But the entire 
genus is exclusively boreal, being only found in Europe and the 
northern countries of America and Asia. The long and sharp¬ 
winged Grouse, or Pterodes of Temminck, which represent, or 
rather replace these birds in the arid and sandy countries of 
Africa and Asia, a single species inhabiting also the southern 
extremity of Europe, we consider, in common with all modern 
authors, as a totally distinct genus. That group, composed of 
but few species, resort to the most desert regions, preferring dry 
and burning wastes to the cool shelter of the woods. These 
oceans, as they might be termed, of sand, so terrific to the eye 
and the imagination of the human traveller, they boldly venture 
to cross in large companies in search of the fluid so indispensable 
to life, but there so scarce, and only found in certain spots. 
Over the intervening spaces they pass with extraordinary rapidity, 
and at a great elevation, being the only gallinaceous birds furnished 
with wings of the form required for such flights. This however 
is not the only peculiarity in which they aberrate from the rest 
of their order, and approach the Pigeons, being said to lay but few 
eggs, the young remaining in the nest until they are full-fledged, 
and fed in the mean time by the parents. 
The Grouse dwell in forests, especially such as are deep, 
and situated in mountainous districts; the Bonasiee however, and 
