About the breeding of these birds we are very imperfectly informed; we know, however, that in the north of Russia they assemble in great numbers, and build their nests upon the shore, or upon small islands, sometimes in hollow trees. We know, likewise, that their nest is composed of dry broom (_Genista_) and grasses, lined with feathers, and that their eggs, eight to twelve in number, are of a dirty white, or greenish brown colour, but we are ignorant either of the duration of their incubation, or of the manner in which they educate their progeny. THE GREEN-HEADED GOOSANDER. The GREEN-HEADED GOOSANDER (_Mergus merganser_) differs from the preceding species not only in its greater size, but in the structure of its bill, which is elongated and compressed at its sides. In his summer dress the male is blackish green upon the head and upper neck; the upper back, shoulders, and margins of the wings are black; the whole under surface and the upper wing-covers are of a beautiful yellowish red; the wing-spot is white. The wing-quills are black, the lower tail-covers grey, finely marked with black, and the tail-feathers grey. The eye is reddish yellow, beak coral-red, and foot pale red. The female has the upper head and nape brown, the back-feathers blueish grey, the under surface of her body and the wing-spot white; the fore parts of her breast and sides are grey, marked with a darker and a lighter shade. After the summer moult the plumage of the male is very similar to that of the female, but somewhat more beautiful. The length of this species is from thirty to thirty-two inches; breadth, forty to forty-two inches; length of wing, twelve inches; length of tail, three inches.