Adult Male. Plate CCXLVII. Fig. 1.
Bill about the length of the head, very broad, as deep as broad at the base, depressed and flattened towards the end, which is rounded. Upper mandible with a short abrupt prominence at the base, its dorsal line on the prominence straight, at its fore edge abruptly sloping, then slightly concave, and at the end curved, the ridge on the prominence very broad and nearly flat, towards the end broadly convex, the sides convex, the edges obtuse with about thirty lamellæ, the unguis very large, and elliptical. Nostrils subbasal, elliptical, very large, pervious, nearer the ridge than the edge, and placed on the lower side of the basal prominence. Lower mandible flat, with the angle long, rather narrow, rounded, the dorsal line slightly convex, the edges with about twenty-five lamellæ, the unguis nearly circular and very large.
Head large. Eyes rather small. Neck of moderate length, thick. Body large, and much depressed. Wings rather small. Feet very short, placed rather far behind; tarsus very short, compressed, having anteriorly in its whole length a series of small scutella, and above the outer toe a partial series, the rest covered with reticular angular scales. Hind toe small, with a free membrane beneath; anterior toes double the length of the tarsus, united by reticulated membranes having a sinus on their free margins, the inner with a lobed marginal membrane, the outer with a thick edge, the third and fourth about equal and longest. Claws small, that of first toe very small and curved, of middle toe largest, with a dilated inner edge, of the rest slender, all obtuse.
Plumage dense, soft, blended. Feathers on the fore part of the head extremely small, on the neck velvety. Wings rather short, narrow, pointed; primary quills curved, strong, tapering and pointed, the first longest, the second very little shorter, the rest rapidly graduated; secondary broad and rounded, the inner elongated and tapering. Tail very short, narrow, wedge shaped, of fourteen stiff narrow feathers.
Basal prominence and sides of the bill black, the sides towards the end bright red, the unguis flesh-colour, with a black line on each side. Iris bright yellow. Feet carmine on the outer side, orange-red on the inner, the webs greyish-black. The general colour of the plumage is brownish-black, on the upper parts glossed with blue, lighter on the lower. The outer secondary quills are white, and there is a spot of the same under the eye.
Length to end of tail 22 inches, to end of wings 19 1/4, to end of claws 24 1/2; extent of wings 39; wing from flexure 12; tail 3 1/2; bill 1 8/12, along the edge of lower mandible 2 7/12; tarsus 1 11/12; middle toe 3, its claw 5/12. Weight 3 lb. 10 oz.
Adult Female. Plate CCXLVII. Fig. 2.
In the Female the basal prominence of the bill is much less elevated, and the colour of the whole bill is dusky. The iris and feet are as in the Male, but of duller tints. The general colour of the plumage is a sooty brown, the breast and abdomen lighter. There are two whitish spots on each side of the head, one near the base of the upper mandible, the other behind the eye; the outer secondary quills are white as in the Male.
Length to end of tail 22 inches, to end of wings 18, to end of claws 25 1/2; extent of wings 38; wing from flexure 11 1/4; tail 3 1/2; bill 1 7/12, along the edge of lower mandible 2 7/12; tarsus 1 3/4; middle toe 2 10/12, its claw 5/12. Weight 3 lb. 3 oz.
The down of this species is similar to that of the Eider Duck, and apparently of equal quality.