INDEX 



Accipitres, descent of, 49. 

 Acquired characters, 311. 

 Africa and South America, continuity 



of, 77. 

 Air-sacs, number of, 17. 



— naso-pharyngeal, 18. 



— of Bustard, 18, 148, 155. 



Adjutant, 18, 156. 



Emu, 19, 166. 



— origin of, 19. 



— ot Musk Duck, 19. 



Frigate-Bird, 150. 



Ruffed Grouse, 155. 



Albinism, 308. 



Anastomus, remarkable beak of, 362. 

 Anseres, origin of, 49. 

 Antarctica, existence of, 76. 

 Aquintocubitalism, meaning of, 409. 

 Archseopteryx, characters of, 35, 41. 



— wing of, 263, 266, 374. 



— tail of, 266. 



— feathers of, 269. 



Arctic sub-region, birds of, 64. 

 Arteries, transformation of, 438. 

 Asymmetry, instances of, 369. 

 Asyngamic forms, 342. 

 Auks, evolution of, 450. 



— systematic position of, 55. 

 Australian region, birds of, 72. 

 Aves, numerical strength of, 60. 



B 



Barbets, peculiar distribution of, 78. 

 Beak, modifications of, 411. 

 Birds, characters of, i, 5, 30. 



— flightless, 37, 69, 73, 123. 



— descent of, 38, 56. 



— classification of, 48. 



— Ethiopian, 65. 



— extinct, 69. 



— Neotropical, 75. 



— fossil, 77. 



-^ size in relation to latitude, 85. 



— effect of climate on, 86. 



Birds, effect of storms on, 87. 



— fertilising flowers, 106. 



— seed dispersal by, 108. 



— checks upon reptiles, 115. 



— enemies of, 116. 



— destroyed by crabs, 116, 117. 

 pigs, 117. 



— parasitic, 127, 132. 



— sharing burrows with reptiles, 127. 



— polyandrous, 134. 



— gregarious habits, 135. 



— strange sleeping postures, 139. 



— food-storing, 140. 



— struggle for existence, 140. 



— tournaments of, 156. 



— weapons of, 160. 



— dances of, 161. 



— song of, 165. 



— music of, 166. 



— windpipes of, i6g. 



— reversal of sexual role in, 171. 



— ancient types of, 174. 



— origin of nests, 174-93. 



— burrowing, 175. 



— nests of, 176. 



— eggs of, 195. 



— brooding habits of, 213 et seq. 



— striped colours of, 252. 

 Bittern, coloration of, 322. 

 Black Cock, display of, 157. 

 Bower-birds, strange habits of, 164. 

 Bustard and Bee-eaters, 125. 



— characters of, 53. 



— display of, 155. 



Caeca, forms of, 21. 

 Canary, origin of, 340. 

 Caracara, causes of increase of, 114. 

 Cariama, transformation of, 442. 

 Carrion-hawk. See Caracara. 

 Cassowaries, specific forms of, 359. 

 Coloration, effect of light on, 81. 

 moisture on, 82, 84. 



— striped, meaning of, 252. 



— protective, 322. 



455 



