Bill about the length of the head or shorter, higher than broad at the
base, depressed toward the end, the margins parallel, slightly dilated
towards the end, which is rounded, the frontal angles rather pointed;
upper mandible with the dorsal line generally declinate, but various
at the base, being often prominent, the ridge broad at the base,
narrowed at the middle, enlarged and convex at the end, the sides
nearly erect at the base, gradually more declinate, the edges soft and
internally lamellate, the unguis oblong and decurved; lower mandible
flattened, being but slightly convex, with the angle very long and
rather narrow, the dorsal line very short and straight, the edges
internally lamellate, the unguis flat, obovato-elliptical. Nostrils
submedial, linear-oblong, rather large, near the ridge, in an oblong
depression covered with the soft membrane of the bill. Head rather
large, compressed, convex above; neck of moderate length, rather
thick; body full, depressed. Feet very short, strong, placed rather
far behind; tarsus very short, compressed, anteriorly with narrow
scutella continuous with those of the middle toe, and having another
series commencing half-way down and continuous with those of the outer
toe; hind toe small, with an inner expanded margin; middle toe nearly
double the length of the tarsus, outer a little shorter, all
scutellate. Claws small, compressed, that of the first toe very small
and curved. Plumage dense, firm, blended. Wings shortish, narrow,
pointed, first and second quills longest; inner secondaries elongated
and tapering. Tail very short, rounded or cuneate, of fourteen or more
feathers. Œsophagus rather wide, considerably dilated at the lower
part of the neck; stomach an extremely muscular, roundish gizzard;
intestine long and wide; cœca long. Trachea of the males with a
transverse, bony, unsymmetrical dilatation at the inferior larynx.
* Bill of ordinary length, broad, without enlargements at the
base, unguis small, decurved.