Bill longer than the head, strong, broader than high, unless towards the curved extremity; upper mandible with its dorsal line slightly concave, at the tip decurved, its ridge broad and nearly flat at the base, narrowed and more convex towards the end, the sides separated from the ridge by a narrow groove, convex, the edges sharp, direct, irregularly jagged, with a prominence at the commencement of the curve at the elongated, compressed, tapering, decurved point; lower mandible with the angle extremely long, narrow, the membrane bare and dilatable into a small pouch, the very short dorsal line decurved, the sides erect at the base, convex in the rest of their extent, the edges sharp, much inflected, irregularly jagged, at the tip narrow and decurved. Nostrils basal, linear, inconspicuous. Head of moderate size, oblong; neck of moderate length, stout; body rather slender. Feet very short, stout; tibia very short; tarsus extremely short, feathered; toes all placed in the same plane, and connected by short deeply emarginate webs, which run out narrow along the sides, scutellate above, first small, second shorter than fourth, third much longer. Claws strong, compressed, curved, acute, that of the third toe long, with the inner edge pectinate. Plumage compact, glossy; feathers of the head, neck, and back lanceolate. Wings extremely long, pointed, the first quill longest; the rest rapidly diminishing; secondaries very short, the inner long and tapering. Tail very long, deeply forked, of twelve feathers. Tongue exceedingly small, fleshy, flattened; œsophagus very wide; proventricular glands forming a complete belt; stomach very small, roundish, its muscular coat thin, the inner soft and corrugated; no pyloric lobe; intestine of moderate length; cœca extremely small; cloaca globular. 422. 1. Tachypetes Aquilus, Linn. Frigate-Bird.--Man-of-war Bird. Plate CCLXXI. Male. Male with the bill light purplish-blue, white in the middle, the gular sac orange; bare skin around the eye blue; feet light carmine above, orange beneath; general colour of plumage brownish-black, the head, neck, back, breast, and sides, splendent with green and purple, the former predominating on the head, the latter on the back; wings tinged with green; inner secondaries and tail with brown, the shafts of the former black, of the latter brown. Female with a broad white space on the breast, that colour extending forwards along the sides of the neck, and encircling it about the middle; feathers of the back less elongated, and glossy; the dark parts more tinged with brown. Young at first covered with yellowish soft down. _Adult_, 41, 86. Resides constantly on and about the Florida Keys, where it breeds in vast numbers on trees. Ranges over the Gulf of Mexico, Bays of Texas, but rarely seen to the eastward of North Carolina. Tachypetes Aquilus, Bonap. Syn. p. 406. Frigate Pelican, Nutt. Man. v. ii. p. 491.