SEXUAL. 



INDEX. 



SLAVERY. 



463 



i. 279 ; gradation of, in birds, ii. 

 135. 

 Sexual and natural selection, con- 

 trasted, i. 278. 

 Sexual characters, effects of the loss 



of, i. 284 ; limitation of, i. 284. 

 Sexual differences in man, i. 14. 

 Sexual selection, explanation of, i. 

 256, 260, 271 ; influence of, on the 

 colouring of Lepidoptera, i. 403 ; 

 action of, in mankind, ii. 368. 

 Sexual similarity, i. 277. 

 Sharks, prehensile organs of male, 



ii. 1. 

 Sharpe, R. B., on Tanysiptera sylvia, 

 ii. 165 ; on Ceryle, ii. 173 ; on the 

 young male of Dacelo Gaudichaudi, 

 ii. 188. 

 Shaw, Mr., on the pugnacity of the 



male salmon, ii. 3. 

 Shaw, J., on the decorations of birds, 



ii. 71. 

 Sheep, danger-signals of, i. 74 ; sex- 

 ual differences in the horns of, i, 

 283 ; horns of, i. 289, ii. 246, 259 ; 

 domestic, sexual differences of, late 

 developed, i. 293 ; numerical pro- 

 portion of the sexes in, i. 304 ; 

 mode of fighting of, ii. 249 ; arched 

 foreheads of some, ii, 284. 

 Sheep, Merino, loss of horns in fe- 

 males of, i. 284 ; horns of, i. 289. 

 Shells, difference in form of, in male 

 and female Gasteropoda, i. 324 ; 

 beautiful colours and shapes of, i. 

 326. 

 Shield-drake, pairing with a com- 

 mon ducl^, ii. 114; New Zealand, 

 sexes and young of, ii. 206. 

 Shooter, J., on the Kaffirs, ii. 347 ; 

 on the marriage - customs of the 

 Kaffirs, ii. 373. 

 Shrew-mice, odour of, ii. 279. 

 Shrike, Drougo, ii. 179. 

 Shrikes, characters of young, ii. 



185. 

 Shuckard, W. E., on sexual differ- 

 ences in the wings of Hymeuoptera, 

 i. 435. 

 Shyness of adorned male birds, ii. 



97. 

 Siagonium, proportions of the sexes 

 in, i. 314 ; dimorphism in males of, 

 i. 374. 



SiAM, proportion of male and female 

 births in, i. 303. 



Siamese, general beardlessness of the, 

 ii. 321 ; notions of beauty of the, 

 ii. 345 ; hairy family of, ii. 378. 



SiEBOLD, C. T. von, on the auditory 

 apparatus of the stridulant ortho- 

 ptera, i. 353. 



Sight, inheritance of long and short, 

 i. 118. 



Signal-cries of monkeys, i. 57. 



SiLK-MOTll, difterence of size of the 

 male and female cocoons of the, i. 346; 

 pairing of the, i. 401 ; male, fer- 

 tilising two or three females, i. 406 ; 

 proportion of the sexes in, i. 309, 

 311; Ailanthus, Prof. Canestrini, 

 on the destruction of its larvae by 

 wasps, i. 311. 



SiMiAD^, i. 195 ; their origin and 

 divisions, i. 213. 



Similarity, sexual, i. 277. 



Singing of the Cicadaj and Fulgoridaj, 

 i. 351 ; of tree-frogs, ii. 27 ; of 

 bii'ds, object of the, ii. 52. 



SiRENiA, nakedness of, i. 148. 



Sirex jicvencus, i. 365. 



SiRiciD^, difference of the sexes in, 

 i. 365. 



Siskin, ii. 85 ; pairing with a canary, 

 ii. 115. 



Sitana, throat-pouch of the males of, 

 ii. 33, 36. 



Size, relative, of the sexes of insects, 

 i. 345. 



Skin, movement of the. i. 19 ; naked- 

 ness of, in man, i. 148 ; colour of 

 the, i. 241. 



Skin and hair, correlation of colour 

 of, i. 248. 



Skull, variation of, in man, i. 108; 

 cubic contents of, no absolute test 

 of intellect, i, 145; Neanderthal, 

 capacity of the, i. 146 ; causes of 

 modification of the, i. 147 ; differ- 

 ence of, in form and capacity, in 

 dift'ereut races of men, i. 216 ; vari- 

 ability of the shape of the, i. 226 ; 

 differences of, in the sexes in man, 

 ii. 317 ; artificial modifications of 

 the shape of, ii. 340. 



Skunk, odour emitted by the, ii. 279. 

 Slavery, prevalence of, i. 94 ; of 

 women, ii. 366. 



