Birds of America
By John James Audubon, F. R. SS. L. & E.
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.