From Mr. Swainson's minute description we learn that the colour of the bill and claws is blueish black. The face is white, and a band of blackish-brown and white crosses the throat. The egrets or ear feathers are tipped with blackish-brown, the inner webs being white varied with wood-brown. The whole of the back is marked with undulated lines or fine bars of dark umber-brown, alternating with white: on the greater wing coverts the white is replaced by pale wood-brown. The primary and secondary feathers are wood-brown, margined inwards with white. They are crossed by umber-brown bars on both webs, the intervening spaces being finely speckled with the same. On the tertiary feathers, the wood-brown is mostly replaced by white. The tail-feathers are white, deeply tinged inwards by wood-brown, and crossed by bars of umber-brown; the tips are white. The chin is white. The throat is crossed by the band already mentioned, behind which there is a large space of pure snow white, that is bounded on the breast by blotches of liver-brown situated on the tips of the feathers. The belly and long plumage of the flanks are white, crossed by narrow bars of dark brown. The under tail coverts, thighs, and feet are pure white. The linings of the wings are pure white with the exception of a brown spot on the tips of the great interior coverts. The bill is strong, curved from the base, moderately compressed towards the tip, with a very obtuse ridge. The facial disk is small, and incomplete above the orbit. The egrets are more than two inches long, each composed of six or seven feathers, and situate behind the upper end of the black band bounding the face. The folded wings fall about three inches and a half short of the tail, which is rounded, the outer feathers being an inch shorter than the central ones. The plumage of the sides of the belly is long, and hangs down over the thighs. The thigh feathers are very downy, but are not long. The tarsi are rather long, and the toes are moderately long; they are clothed to the roots of the nails by a close coat of hairy feathers. The claws are strong, sharp, and very much curved. The length of the bird from the tip of the bill to the end of the tail is 21 inches 6 lines; and the length of the longest quill feather is 12 inches six lines. * * * * * THE COCK OF THE PLAINS, _Tetrao,[3] (Centrocercus,) Urophasianus,_ SWAINSON. This bird, which was first mentioned by Lewis and Clark,[4] has since become well known to the fur traders that frequent the banks of the Colombia. Several specimens have been sent to England by the agents of the Hudson's Bay Company. Mr. David Douglas has published the following account of the manners of the species, the only one hitherto given. [3] Or Grouse. [4] The adventurous travellers to the Source of the Missouri.