Family XXXII. TETRAONINAE. GROUSE. GENUS II. LAGOPUS. PTARMIGAN
Bill short, robust; upper mandible with its dorsal outline
decurved, the ridge indistinct and rounded, the sides convex,
the edges overlapping, the tip declinate, thin-edged, rounded;
lower mandible with the angle of moderate length and rounded,
the dorsal line convex, the sides rounded, the edges a little
inclinate, the tip rounded; nasal sinuses large and covered with
feathers, leaving the ridge narrow between them. Nostrils basal,
roundish, concealed by the feathers. Head small, ovate; neck
rather long; body bulky. Feet rather short, stout; tarsus
feathered, as are the toes, which have two or three terminal
scutella; hind toe extremely short, lateral toes equal. Claws
slightly arched, depressed, thin-edged, rounded. Plumage full
and compact, the feathers rounded. Wings short, convex, the
primaries strong, narrow, tapering, the third longest, the
fourth and second little shorter. Tail short, nearly even, of
more than twelve broad feathers.