Sarkidiornis Eyton., Monogr. Anatidse, pp. 20,102 (1838).
Type by mon., Anser melanotus Pennant.
The genus Sarkidiornis differs from all other Indian genera in having a spur on the shoulder of the wing, a feature which was formerly considered of sufficient importance to constitute the genus into a family by itself. The bill is of moderate length,, furnished in the male with a fleshy knob on the base, which becomes greatly swollen in the breeding-season (see fig. 69); the tail of twelve feathers is long and graduated; the lower end of the trachea is expanded on one side only; the hind toe is narrowly lobed.