DISUSE. 
INDEX. 
DUCKS. 
425 
geographical, as evidence of specific 
distinctness in man, i. 218. 
Disuse, effects of, in producing rudi- 
mentary organs, i. 18 ; and use of 
parts, effects of, i. 116; of parts, 
influence of, on the races of men, i. 
247. 
Divorce, freedom of, among the Char- 
ruas, ii. 372. 
Dixok, E. S., on the habits of the 
guinea-fowl, i. 270 ; on the pairing 
of different species of geese, ii. 114 ; 
on the courtship of peafowl, ii. 
121 . 
Dobrizhoffer, on the marriage-cus- 
toms of the Alipones, ii. 374. 
Dogs, suffering from Tertian ague, i. 
13 ; memory of, i. 45 ; domestic, 
progress of, in moral qualities, i. 50 ; 
distinct tones uttered by, i. 54 ; pa- 
rallelism between his affection for 
his master and religious feeling, i. 
68; sociability of the, i. 74; sym- 
pathy of, with a sick cat, i. 77 ; 
sympathy of, with his master, i. 77 ; 
possible use of the hair on the fore- 
legs of the, i. 1 93 ; races of the, i. 229 ; 
diverging when drawing sledges over 
thin ice, i. 46 ; dreaming, i. 46, 
158 ; exercise of reasoning facul- 
ties by, i. 48 ; their possession of 
conscience, i. 78; numerical pro- 
portion of male and female births 
in, i. 304; sexual affection between 
individuals of, ii. 270; howling at 
certain notes, ii. 333; rolling in 
carrion, ii. 281. 
Dolichocephalic structure, possible 
cause of, i. 148. 
Dolphins, nakedness of, i, 148. 
Domestic animals, races of, i. 229 ; 
change of breeds of, ii. 369. 
Domestication, influence of, in re- 
moving the sterility of hybrids, i. 
222 . 
D’Orbigny, a., on the influence of 
dampness and dryness on the colour 
of the skin, i. 242 ; on the Yura- 
caras, ii. 347. 
Dotterel, ii. 203. 
Doubleday, E., on sexual differences 
in the wings of butterflies, i. 345. 
Doubleday, H., on the proportion 
of the sexes in the smaller moths, 
i. 311 ; on the attraction of the 
males of Lasiocampa quercus and 
Saturnia carpini by the female, i. 
312 ; on the proportion of the sexes 
in the Lepidoptera, i. 312 ; on the 
ticking of Anohium tessellatum, i. 
385 ; on the structure of Ageronia 
feronia, i. 387 ; on white butter- 
flies alighting upon paper, i. 400. 
Douglas, J. W., on the sexual dif- 
ferences of the Hemiptera^ i. 349 ; 
on the colours of British Homo- 
ptera^ i. 352. 
Down, of birds, ii. 80. 
Draco, gular appendages of, ii. 33. 
Dragonet, Gemmeous, ii. 7. 
Dragon-flies, caudal appendages of 
male, i. 344 ; relative size of the 
sexes of, i. 347 ; difference in the 
sexes of, i. 361 ; want of pugnacity 
by the male, i. 364. 
Drake, breeding plumage of the, ii., 
84. 
Dreams, i. 46 ; a possible source of 
the belief in spiritual agencies, i. 
66 . 
Drill, sexual difference of colour in 
the, ii. 291. 
Dromoeus irroratus, ii. 204. 
Dromolxa, Saharan species of, ii. 172. 
Drongo shrike, ii. 179. 
Drongos, racket-shaped feathers in 
the tails of, ii. 73, 83. 
Dryness, of climate, supposed in- 
fluence of, on the colour of the 
skin, i. 242. 
Drgopithecus, i. 199. 
Duck, harlequin, age of mature plu- 
mage in the, ii. 213 ; breeding in 
immature plumage, ii. 214. 
Duck, long-tailed, preference of male, 
for certain females, ii. 122. 
Duck, pintail, pairing with a wigeon, 
ii. 114. 
Duck, voice of the, ii. 60 ; pairing 
with a shield-drake, ii. 114; imma- 
ture plumage of the, ii. 188. 
Duck, wild, sexual differences in the, 
i. 268 ; speculum and male charac- 
ters of, i. 291 ; pairing with a pin- 
tail drake, ii. 115. 
Ducks, dogs and cats recognised by, 
ii. 110 ; wild, becoming polygamous 
under partial domestication, i. 270, 
