The upper surface of the wings, scapulars, and back in this bird, was a brownish black; the urupigium, white; the head, chin, and neck, of a delicate grey, or blue grey. The back is shaded off towards the neck, which becomes of a soft and beautiful leaden colour, of more light and delicate tints as it proceeds around the front part of the neck, extending towards the breast; eyelids black: the upper surface of the tail was of a light black; shaded with white in a very delicate and beautiful manner. At first, this appearance was supposed only to be the result of the different lights in which the bird was occasionally placed; but subsequent observations confirmed its being the marked colour. On examining one of the tail-feathers plucked from the bird, it was found delicately tinted; the shaft diminishing gradually as it proceeded from the quill to the extremity, until it terminated in a very fine filament, projecting one-eighth of an inch from the plume; this was observed in the whole of the upper and large tail-feathers. The plume as it came off on each side from the base, terminated in a beautiful downy appearance; tail-feathers underneath of a lighter colour—vent (crissum) white, which gives a light delicate appearance to the edge of the feather. The breast and abdomen are of a snow-white; under surface of the wings, upper line along the wing-bones, and a little below, brownish-black; middle white, (excepting a few brown feathers near the axilla,) forming a continuous broad white line the whole length of the under surface of the wings; lower feathers base white, tips black, under surface of the pen-feathers black; shafts white. At the inferior part of the external angle of the eye, around the margin of the lid, a narrow white mark extends for the length of seven-eighths of an inch. A diffused black-mark was situated over, and extended to the inner angle of the eye, terminating near the base of the bill in lighter shades of the same colour, forming an agreeable contrast with the delicate leaden hue extending over the head and neck. Bill blackish; upper surface horny, (shaded with light black at some parts,) extending, of a similar appearance, to the hooked process of the upper mandible. At the lower part of the inferior mandible, this horny appearance also extends to within an inch of the tip. Irides brown; the first pen-feather the longest; feet and legs marbled, the web marbled blue, more at the anterior edges, and between the second and third toes; claws of the toes turned outwards, (to the right.) There is a very minute tubercle at the posterior, and lower part of the tarsus, which is considered by some as a rudiment of thumb, and I suppose to be that alluded to by Lesson, when he says of this genus, “pouce sans ongles.”