_Male_, 14-3/4, wing, 8-1/4. Melville Island. Churchill River. Tetrao lagopus, Sabine, Richardson, &c. Tetrao (Lagopus) mutus, Ptarmigan, Swains. & Rich. F. Bor. Amer. v. ii. p. 350. Common Ptarmigan, Tetrao mutus, Aud. Orn. Biog. v. v. p. 196. 303. 3. Lagopus rupestris, Gmel. Rock Ptarmigan. Plate CCCLXVIII. Male and Female. Plate CCCCXVIII. Fig. 1. Bill very short, thick, convex (stronger than that of _L. americanus_), with the ridges on the lower mandible faint; claws elongated, arched, with the sides sloping, the edges thin and nearly parallel, the tip narrowed, (broader than in _L. albus_). Tail short, slightly rounded, of fourteen feathers, independently of the long incumbent coverts. Bill black, claws dusky, with the edges and tip inclining to yellowish-grey. In winter, the plumage white, excepting the shafts of the primaries, which are brownish-black, and the tail-feathers, which are black, narrowly tipped with white, and with the base of the same colour. In summer, the plumage variegated with black, reddish-yellow, and white; the feathers being chiefly of the first colour, transversely and irregularly banded with reddish-yellow, and terminally margined with white; lower parts more broadly and regularly barred with brownish-black and light reddish-yellow; edge of wing, alula, primary coverts, nearly all the secondary coverts, primaries, and outer secondaries white, as are the lower surface of the wing, the axillars, and some of the feathers on the abdomen, as well as those on the feet, the latter tinged with yellowish; shafts of primaries brownish-black; tail as in winter, but with the lateral feather white on a great part of the outer web. Female similar, with the bands broader. _Male_, 13-1/2, wing, 7-10/12. Breeds from Labrador to the Arctic Seas. Rocky Mountains. Abundant. Migratory. Tetrao (Lagopus) rupestris, Swains. & Rich. F. Bor. Amer. v. ii. p. 354. Rock Grouse, Nutt. Man. v. i. p. 610. Rock Grouse, Tetrao rupestris, Aud. Orn. Biog. v. iv. p. 483. 304. 4. Lagopus leucurus, Swains. White-tailed Ptarmigan. Plate CCCCXVIII. Adult in winter. Claws slightly arched, depressed, broad, thin-edged, rather pointed; tail rather short, slightly rounded, of fourteen feathers. Plumage in winter entirely pure white. In summer, the head and neck barred with blackish-brown and brownish-white; upper parts blackish-brown, barred with reddish-yellow; breast, belly, and sides pale reddish-yellow, broadly barred with blackish-brown; tail white. Tetrao (Lagopus) leucurus, White-tailed Grouse, Swains. & Rich. F. Bor. Amer. v. ii, p. 356. White-tailed Grouse, Nutt. Man. v. ii. p. 612. White-tailed Grouse, Tetrao leucurus, Aud. Orn. Biog. v. v. p. 200. FAMILY XXXIII. RALLINÆ. RAILS.