Family XXXIX. ANATINAE. DUCKS.
GENUS IV. ANAS, Linn. DUCK
Bill about the length of the head, somewhat higher than broad at the base, depressed and widened towards the end, rounded at the tip; tipper mandible with the dorsal line sloping, and a little concave, the ridge at the base broad and flat, towards the end broadly convex, as are the sides, the edges soft and rather obtuse, the marginal lamellae numerous, oblique; unguis decurved, obovate; nasal groove elliptical, sub-basal, filled by the soft membrane of the bill; lower mandible flattened, slightly recurvate, with the angle very long and narrow, the unguis roundish, the lamellae numerous. Nostrils sub-basal, elliptical, near the ridge. Head of moderate size, oblong, compressed; neck rather long and slender; body full, depressed. Feet short, stout, placed a little behind the centre of the body; tibia bare a little above the joint; tarsus short, somewhat compressed, anteriorly with small scutella, laterally and behind with angular scales; hind toe extremely small, with a very narrow membrane; third toe longest, fourth a little shorter, but longer than second; all covered with numerous oblique scutella; anterior connected by reticulated membranes. Claws small, arched, compressed, rather acute. Plumage dense, soft. Wings of moderate length, acute; second quill longest, first very little shorter; inner secondaries elongated and tapering; tail short, much rounded, of sixteen feathers. OEsophagus rather narrow, dilated on the lower part of the neck; stomach an extremely muscular, transversely elliptical gizzard; intestine long and rather wide; coeca long. Trachea of the males with a transverse bony unsymmetrical dilatation at the inferior larynx.