BIRDS—TETRAONIDAE. 619 
Family TETRAONIDAE. The Grouse. 
As already stated, the Tetraonidae are pre-eminently characterised among gallinaceous birds 
by their densely feathered tarsi, and by the feathers of the nasal fossa or groove, which fill it 
completely, and conceal the nostrils. The toes are usually naked, (feathered to the claws in 
the ptarmigans,) and with pectinations of scales along the edges. The tail feathers vary from 
sixteen to eighteen and even twenty in number; the tail is rounded, acute, or forked. The 
orbital region is generally somewhat bare, with a naked stripe above the upper eyelid, beset 
by short fringe-like processes. 
The following synoptical table will give a general view of the North American Tetraonidae, 
although the arrangement is probably much more artificial than natural. The species of Zetrao 
and Bonasa inhabit wooded regions; Lagopus belongs to the more arctic portions of the 
continent and the snowy ridges of the Rocky mountains, while the others are found in the 
great prairies of the west, Centrocercus being confined to the sterile plains covered with sage or 
wormwood, 
Synopsis of genera. 
A. Legs feathered to and on the basal membrane of the toes. No ruff on the side of the 
neck, which, however, has an extensible bare space. 
TrTrAo.—Tail broad, nearly even, or truncate, and rounded laterally ; two-thirds the 
wing. Nasal fossae scarcely half the culmen. 
CrntROcERCUS.—Tail excessively lengthened and cuneate ; longer than the wings. Nasal 
fossae two-thirds the culmen. Shafts of feathers on the lower throat very spinous. 
PeprocarTes.— Tail very short, but graduated, and with the two middle feathers (perhaps 
tail coverts) lengthened beyond the rest, and two-thirds as long as the wing; the 
next longest, half the wing. Nasal fossae not half the length of culmen. Shafts of 
throat feathers normal. 
B, Legs scarcely feathered to the extreme base of tarsus, the lower joint of which is bare, 
with large transverse scutellae. 
Cuprponta.—Tail very short, truncate, but laterally graduated ; half the wings. Sides 
of neck with long, pointed, or lanceolate, stiff feathers. Nasal fossae scarcely one- 
third the culmen. 
C. Legs feathered to the claws. 
Lacorus.—Tail about two-thirds the wing, truncate ; of sixteen to eighteen feathers. 
Most species becoming white in winter; none of the other genera exhibiting this 
peculiarity. 
D. Lower half of tarsi bare, with two rows of scutellae anteriorly, 
Bonasa.—Sides of neck with a ruff of broad, truncate, soft feathers. Tail very broad, 
square, as long as the wings, 
