INDEX. 



t)53 



Ocelli of birds, formation and va- 

 riability of the, 422. 



Ocelot, sexual differences in the 

 coloring of the, 529. 



Ocyphaps lophotes, S96. 



Odonata, 250. 



Odonestis potatoria, sexual differ- 

 ence of color In, 312. 



Odor, correlation of, with color of 

 skin, 192; emitted by snakes in 

 tlie breeding-season, 348; of 

 mammals, 524. 



Oecanthus nivalis, difference of 

 color in the sexes of, 287. 



pellucidus, 287. 



Ogle, Dr. W., relation between 

 color and power of smell, 18. 



Oidemia, 486. 



Oliver, on sounds produced by 

 Pimelia striata, 303. 



Omaloplia brunnea, stridulation 

 of, 300. 



Onitis, furcifer, processes of ante- 

 rior femora of the male, and on 

 the head and thorax of the fe- 

 male, 295. 



Onthophagus, 293. 



rangifer, sexual differences 



of, 294; variation in the horns of 

 the male, 295. 



Ophidia, sexual differences of, 357. 



Ophidlum, 343. 



Opossum, wide range of, in Amer- 

 ica, 165. 



Optic nerve, atrophy of the, 

 caused by destruction of the eye, 

 31. 



Orang-Outan, 556; Bischoff on the 

 agreement of the brain of the, 

 with that of man, 6; adult age 

 of the, 8; ears of the, 14; ver- 

 miform appendage of, 20; hands 

 of the, 48; absence of mastoid 

 processes in the, 51; platforms 

 built by the, 64; alarmed at the 

 sight of a turtle, 71; using a 

 stick as a lever, 79; using mis- 

 siles, 79; using the leaves of the 

 Pandanus as a night covering, 

 80; direction of the hair on the 

 arms of the, 147; Its aberrant 

 characters, 149; supposed evolu- 

 tion of the, 173; voice of the, 522; 

 monogamous habits of the, 585; 

 male, beard of the, 526. 



Oranges, treatment of, by men- 



Orange-tip butterfly, 305, 308, 309. 

 Orchestia Darwinii, dimorphism 

 of males of, 265. 



Tucuratinga, limbs of, 263, 



268. 



Ordeal, trial by, 93. 



Oreas canna, colors of, 531. 



Derblanus, colors of, 531, 



538. 



Organs, prehensile, 205; utilized 

 for new purposes, 565. 



Organic scale, von Baer's defini- 

 tion of progress in, 159. 



Orioles, nidiflcation of, 447. 

 Oriolus, species of, breeding in 

 immature plumage, 479. 



melanocephalus, coloration 



of the sexes in, 464. 



Ornaments, prevalence of similar, 

 175; of male birds, 363; fondness 

 of savages for, 568. 



Ornamental characters, equal 

 transmission of, to both sexes. 

 In mammals, 536; of monkeys, 

 543. 



Ornithoptera craesus, 246. 



Ornithorhynchus, 162; reptilian 

 tendency of, 164; spur of the 

 male, 498. 



Orocetes erythrogastra, young of, 

 482. 



Orrony, Grotto of, 21. 



Orsodacna atra, difference of color 

 in the sexes of, 291. 



Orthoptera, 280; ■ metamorphosis 

 of, 231; stridulating apparatus 

 of, 280, 284; colors of, 286; rudi- 

 mentary stridulating organs In 

 female, 284; stridulation of the, 

 and Homoptera, discussed, 286. 



Ortygornis gularls, pugnacity of 

 the male, 359. 



Oryctes, stridulation of, 300; sex- 

 ual differences in the stridulant 

 organs of, 302. 



Oryx leucoryx, use of the horns 

 of, 505, 513. 



Osphranter rufus, sexual differ- 

 ence in the color of, 529. 



Ostrich, African, sexes and incu- 

 bation of the, 473. 



Ostriches, stripes of young, 459. 



Otaria Jubata, mane of the male, 

 516. 



■ — ■ — nigrescens, difference in the 

 coloration of the sexes of, 530. 



Otis bengalensis, love-antics of 

 the male, 376. 



tarda, throat-pouch of the 



male, 368; polygamous, 215. 



Ouzel, ring-, colors and nidiflca- 

 tion of the, 449. 



, water-, colors and nidiflca- 

 tion of the, 449. 



Ovibos moschatus, horns of, 501. 



Ovipositor of Insects, 204. 



Ovis cyoloceros, mode of fighting 

 of, 504, 509. 



Ovule of man, 7. 



Owen, Prof., on the Corpora 

 Wolfflana, 11; on the great toe In 

 man, U; on the nictitating 

 membrane and semilunar fold, 

 17; on the development of the 

 posterior molars in different 

 races of man, 20; on the length 

 of the coeoum in the Koala, 20; 

 of the coccygeal vertebrae, 22; 

 on rudimentary structures be- 

 longing to the reproductive sys- 

 tem, 23; on abnormal conditions 

 of the human uterus, 37; on the 

 number of digits In the Ichthy- 



