124 
ROCK PTARMIGAN. 
of which two are incumbent, less strong, and longer than the rest by two- 
twelfths of an inch. 
Bill black ; superciliary membrane scarlet ; claws dusky, towards the end 
yellowish. The plumage is pure white, with the exception of a broad band 
of black from the upper mandible to the eye, and for a short space behind it ; 
the shafts of the six outer quills, which are brownish-black, and all the tail- 
feathers, the two middle excepted, they being of a deep greyish-black colour, 
with a terminal narrow band of white. 
Length to end of tail 132 inches, to end of wings 12 ; wing from flexure 
8; tail 42, tarsus lfv ; hind toe T 2 ? , its claw tv; middle toe 4^, its claw T s ? . 
Male in summer. 
In summer, the plumage differs little in texture, with the exception of 
that on the feet, which is short and thin on the tarsi, worn on the base of 
the toes, of which the soles and half of the upper surface are denuded. The 
bill and claws are of the same colour as in winter ; but the plumage is 
variegated with black, reddish-yellow, and white. The upper parts may be 
described as black, transversely and irregularly banded and spotted with 
yellowish-red* the feather terminally margined with white, there being on 
each feather several bars of yellowish-red running from the margin inwards, 
but leaving a black space in the centre. The lower parts are lighter, more 
broadly and regularly barred with brownish-black and light re.ddish yellow. 
The feathers along the edge of the wing, alula, primary coverts, nearly 
all the secondary coverts, primaries and outer secondaries, white ; as are the 
lower surface of the wing, the axillar feathers^ and some of the feathers on 
the abdomen, as well as those on the feet, the latter being soiled or tingsd 
with yellowish or grey. The shafts of the primaries are brownish-black, and 
the tail is black as in winter, tipped with white, and with the lateral feathers 
having part of their outer web white ; the two middle feathers barred like the 
back. The dimensions of an individual are as follows : 
Length to end of tail 132 inches, to end of wings 112 ; wing from flexure 
7jf ; tail 42 ; bill along the ridge r \ ; tarsus lfV ; middle toe 1} j, its claw T V 
Female in summer. 
The female does not differ materially from the male, the yellow bands 
being only broader and lighter. 
Very great differences are observed in the length and form of the claws, 
they being in some individuals very long, thin-edged, and tapering to a 
rounded point ; in others very short, being worn down to the stump. This 
species is considerably smaller than the Ptarmigan of Scotland, which it 
precisely resembles in its winter plumage. In its summer plumage, however, 
it differs in having the markings larger ; and as yet no specimens have been, 
