I. GENUS AQUILA. Mœhring, Av. Gen. p. 49. (1752.) Large, bill large, strong, compressed, and hooked at the tip; wing long, pointed, very strong; tarsi moderate, feathered to the base of the toes. Tail rather long, rounded or wedge-shaped; toes and claws long; the latter very sharp and curved. Contains about twenty species, which are regarded as the true Eagles. 1. Aquila chrysaetos. (Linn.) The Golden Eagle. The ring-tailed Eagle. Falco chrysaetos and fulvus. Linn., Syst. Nat., I. p. 125. (1766.) Falco canadensis. Linn., Syst. Nat., I. p. 125. (1766.) Aquila nobilis. Pallas, Zoog. Ross. As., I. p. 338. (1811.) Falco niger. Gm., Syst. Nat., I. p. 259. (1788.)? Edw., Birds, pl. 1; Brown, Ill., pl. 2; Buff. Pl. Enl. 409, 410; Wils. Am. Orn., pl. 55, fig. 1; Aud. B. of Am., pl. 181; oct. ed. 1, pl. 12. Very large; tarsi densely feathered to the toes. Adult. Head above and behind and neck behind light-brownish fulvous, much varying in shade in different specimens. Base of the tail pure white, which color varies in extent in different specimens, but generally occupies the greater part of the tail; remaining portion glossy black. All other parts rich purplish-brown, very dark, and nearly black on the under-surface. Primary quills shining black, secondaries purplish-brown, with a violet tinge; tibia and tarsi brownish-fulvous, tinged with ashy; toes yellow. Younger. Entire plumage mixed with fulvous, and with the under-surface of the body paler. Dimensions. _Female_—total length, 33 to 40 inches; wing, about 25; tail, about 15 inches. _Male_—smaller. Hab. Whole of North America; Oregon (Dr. Townsend). Spec. in Mus. Acad., Philada. Obs. We are not without doubts as to the specific identity of the American and the European Golden Eagles. All the American specimens that we have examined are smaller, the bill shorter, and the plumage much darker than those of Europe. We have not at present, however, a sufficient number of either continent, and it unfortunately happens that nearly all our European specimens are young birds, while the American are adults. Mr. Audubon’s plate represents this bird in nearly mature plumage. II. GENUS HALIAETUS. Savigny, Hist. Nat. d’Egypt, I. p. 85. (1809.) Size large; tarsi short, naked, or feathered for a short distance below the joint of the tibia and tarsi, and with the toes covered with scales. Bill large, strong, compressed; margin of upper mandible slightly festooned; wings rather long-pointed; tail moderate; toes rather long; claws very strong, curved, sharp. This genus contains about ten species of all parts of the world, all of which prey more or less on fishes, and are known as Fishing or Sea Eagles.