Birds of America
By John James Audubon, F. R. SS. L. & E.
FAMILY XLV.--COLYMBINAE. DIVERS AND GREBES.
Bill of the length of the head, straight, rather stout, much compressed,
pointed; upper mandible with the dorsal line declinate, almost straight, or
towards the end convex; nasal groove rather long, feathered at the base.
Nostrils basal, linear, direct, pervious. Feet stout, short, placed extremely
far behind; tarsus extremely compressed; toes four, the first very small, and
lobed; the anterior united by webs, which in some are lobed. Plumage
dense, short, glossy, generally silky beneath. Wings small, very narrow,
acute. Tail very short, sometimes extremely small, and forming a slight
tuft. Tongue slender, trigonal, tapering; oesophagus very wide in its whole
length, or narrowed in the anterior part with the proventriculus wide;
stomach generally large, muscular, with a dense rugous epithelium; intestine
rather long and wide; as are the coeca; cloaca globular.