[1498] Darwin, ‘The Descent of Man,’ vol. i. p.  485.

[1499] Wallace, ‘Darwinism,’ p. 270.

[1500] The Gallinaceæ, however, form an exception; though almost wholly terrestrial, they have the most pronounced sexual colours. But they are active and wander much.

[1501] Wallace, ‘Tropical Nature,’ pp. 230, et seq.

[1502] Gould, ‘Handbook to the Birds of Australia,’ vol. ii. p. 383.

[1503] Wood, loc.cit. vol. ii. p. 257.

[1504] Prejevalsky, ‘From Kulja to Lob-nor,’ pp. 92, 94.

[1505] Brehm, ‘Thierleben,’ vol. iii. p. 94.

[1506] Gould, loc. cit. vol. ii. pp. 382, et seq.

[1507] Darwin, ‘The Descent of Man,’ vol. i. p.  62.