Family XXIV. TROCHILINAE. HUMMING-BIRDS.
Bill long, very slender, straight or arched, somewhat depressed at the base, subcylindrical, flexible, acute. Head rather large; neck of moderate length; body moderately robust. Feet very short, rather stout; tarsus extremely short; toes of moderate size; the anterior coherent at the base, and nearly of equal length, the hind toe articulated high on the tarsus; claws rather long, arched, much compressed, very acute. Plumage compact above, soft and blended beneath, often with metallic lustre; wings very long, extremely narrow, falciform, with the first quill longest, the other primaries rapidly diminishing; secondaries extremely short. Tail various, of ten feathers. Tongue very long, slender, with two flat, thin-edged terminal filaments, and extensile by means of the elongation of the hyoid bones, which curve over the head to the fore part of the forehead, and with their muscles slide in a groove, like those of the Woodpeckers. OEsophagus narrow, considerably enlarged about the middle; stomach extremely small, roundish, moderately muscular, its epithelium dense and longitudinally rugous; intestine very short and of moderate width; no coeca; cloaca globular. Trachea simple, but divided very high up on the neck, so that the bronchi are of excessive length, with a large pair of inferior laryngeal muscles.