Family XXXIX. ANATINAE. DUCKS.
Bill of moderate length, stout, straight, depressed toward the end, obtuse, covered with soft skin; upper mandible transversely convex, with the margins internally lamellate, the tip furnished with a decurved horny broad unguis; lower mandible with the angle long and narrow, the crura slender, flattened, the edges internally lamellate, the tip a flattened unguis. Nostrils elliptical, open, sub-basal. Head of moderate size; neck long or of moderate length, slender; body full; legs generally short, stout, with little of the tibia bare; tarsus scutellate; toes four, first small; anterior three palmate. Claws moderate, arched, compressed, obtuse. Plumage very full, dense, soft. Wings of moderate length, curved, acute, outer two quills longest. Tail short, of twelve or more feathers. Tongue fleshy, with a median groove, lateral reversed papillae, laminae, or bristles, and a semicircular thin horny tip; oesophagus narrow, slightly enlarged at the lower part of the neck; stomach a transversely elliptical gizzard, of which the lateral muscles are excessively developed, the epithelium dense, with two concave finding surfaces; intestine long and wide; coeca long, cylindrical, contracted at the base. Trachea various generally much enlarged at the bifurcation, without inferior laryngeal muscles, or only with the slips of the lateral muscles prolonged. Nest generally on the ground; eggs numerous. Young clothed with stiffish down, and able to walk and swim from birth.