The Descent of Man

plumes are erected, so that they meet over the
crown of the head. See his drawing, Fig. 39.)
The male of another kind of grouse (Tetrao
urophasianus), whilst courting the female, has
his "bare yellow oesophagus inflated to a prodigious
size, fully half as large as the body";
and he then utters various grating, deep,
hollow tones. With his neck-feathers erect, his
wings lowered, and buzzing on the ground,
and his long pointed tail spread out like a fan,
he displays a variety of grotesque attitudes. The
oesophagus of the female is not in any way
remarkable. (42. Richardson, 'Fauna Bor. American:
Birds,' 1831, p. 359. Audubon, ibid. vol.
iv. p. 507.)
[Fig. 40. The Umbrella-bird or Cephalopterus
ornatus, male (from Brehm).]
It seems now well made out that the great
throat pouch of the European male bustard
(Otis tarda), and of at least four other species,
does not, as was formerly supposed, serve to