INDEX. 783 



579; arched foreheads of some, COS; merino, loss of liorns in females 

 of, 261; liorns of, 266. 



Shells, difference in form of, in male and female Gasteropoda. 297; 

 beautiful colors and shapes of. 298. 



Shield drake, pairing: with a common duck, 471; New Zealand, 

 sexes and young of, 546. 



Shooter, J., on the Kaffirs, 661; on the marriage-customs of the 

 Kaffirs, 661. 



Shrew-mice, odor of, 604. 



Shrike, Drongo, 524. 



Shrikes, characters of young, 529. 



Shuckard, W. E., on sexual differences in the wings of Hymenop^ 

 tera, 314. 



Shyness of adorned male birds, 457. 



Siagonium, proportions of the sexes in, 286; dimorphism in males 

 of, 339. 



Siatu, proportion of male and female births in, 277. 



Siamese, general beardlessness of the, 639; notions of beauty of 

 the, 660, hairy family of, 687. 



Sidgwick, H., on morality in hypothetical bee community, 113; our 

 actions not entirely directed by pain and pleasure, 136. 



Siebold, C. T. von, on the proportion of sexes in the Apus, 287; on 

 the auditory apparatus of the stridulant Orthoptera, 321. 



Sight, inheritance of long and short, 38. 



Signal -cries of monkeys, 98. 



Silk-moth, proportion of the sexes in. 282, 284; A'ftanthus. Prof. 

 Canestrini, on the destruction of its larvae by wasps. 284; difference 

 of size of the male and female cocoons of the. 315: pairing of 

 the, 360. 



Simiadae, 173; their origin and divisions, 188. 



Similarity, sexual, 254. 



Singing, of the Cicadae and Fulgorid&e, 319; of tree-frogs, 397; of 

 birds, object of the, 417. 



Sireuia, nakedness of, 63. 



Sir ex juvtncwt, 331. 



Siricidae, difference of the sexes in. 331. 



Siskin, 446; pairing with a canary, 472. 



Sitana, throat-prmch of the males of, 402, 406. 



Si/e, relative, of the sexes of insects, 315. 



Skin, dark color of, a protection against heat, 223. 



Skin, movement of the, 14; nakedness of, in man, 63; color of 

 the, 219; and hair, correlation of color of, 225. 



Skull, variation of, in man, 29; cubic contents of.no absolute tost 

 of intellect, 61; Neanderthal, capacity of the, 61; causes of modifica- 

 tion of the, 62; difference of, in form and capacity, in different race* 

 of men. 192; variability of the shape of the, 198; differences of, in 

 the sexes in man, 635; artificial modification of the shape of. 655. 



Skunk, odor emitte;! by the. 603; white tail of, protective, 621. 



Slavery, prevalence of, 133; of women, 677. 



Slaves* difference between field and house-slaves, 224. 



Sloth, ornaments of male, 610. 



Smell, sense of, in man and animals, 19. 



Smith, Adam, on the basis of sympathy, 120. 



