868 



INDEX 



66'2; on sexual preference in dogs, 

 676; on the rejection of a horse by 

 a mare, 617. 



■Wright, W. von, on the protective plu- 

 mage of the Ptarmigan, 605. 



Writing, 194. 



Wyman, Prof., on the prolongation of 

 the coccyx in the human embryo, 

 26; on the condition of the great 

 toe in the human embryo, 28; on 

 the occurrence of the supra-condyloid 

 foramen in the humerus of man, 41 ; 

 on variation in the skulls of the na- 

 tives of the Sandwich Islands, 46; 

 on the hatching of the eggs in the 

 mouths and branchial cavities of 

 male fishes, 218, 449. 



Xenarchus, on the Cicadse, 370. 



Xenophon, selection in mankind advo- 

 cated by, 50. 



Xenorhynehus, sexual difference in the 

 color of the eyes in, 549. 



Xiphophorus Eellerii, peculiar anal fin 

 of the male, 439-440. 



Xyloeopa, difference of the sexes in, 

 384. 



Tarrell, W., on the habits of the Cy- 

 prinids, 329; on Baia clavata, 432; 



on the characters of the mate salmon 

 during the breeding season, 434; on 

 the characters of the rays, 436; on 

 the gemmeous dragonet, 437 ; on the 

 spawning of the salmon, 448; on 

 the incubation of the Lophobranchii, 

 450; on rivalry in song-birds, 479; 

 on the trachea of the swan, 485 ; on 

 the moulting of the AnatidsB, 606; 

 on the young of the waders, 627. 



Yellow fever, immunity of negroes and 

 mulattoes from, 256. 



Touatt, Mr., on the development of 

 the horns in cattle, 309. 



Turacaras, their notions of beauty, 746. 



Zebra, rejection of an ass by a female, 

 698 ; stripes of the, 704. 



Zebus, humps of, 688. 



Zigzags, prevalence of, as ornaments, 

 238. 



Zincke, Mr., on European emigration 

 to America, 191. 



Zootoca vivipara, sexual difference in 

 the color of, 464. 



Zouteveen, Dr., polydactylism, 60; pro- 

 portion of sexes at Cape of Good 

 Hope, 319; spiders attracted by 

 music, 361; on sounds produced 

 by fish, 451-452. 



Zygasnidae, coloration of the, 410. 



