INDEX. 



295 



Surinam toad, 56, 233, 234 

 Sutton on embryonic hermaphrodit- 

 ism, 28, 61 

 Syllids, asexual multiplication, 182 



Tadpoles, 36, 230 



Tapeworm, life-history of, 194 



Temperance, 273, 274 



Temperature, influence of, on sex, 43 



Thury, theory of sex, 29 



Tiger-lily, 209 



Treviranus, 276, 277 ; on influence of 



sperm, 155, 282 

 Tunicates, asexual multiplication, 183; 



alternation of generations, 187 

 Twins, 194 ; sex of, 33, 34 



Ulothrix, reproduction in, 120 



Variation, 11, 12, 155, 156, 277, 281 

 Vines on reproduction in plants, 120 

 Viviparous animals, 229 

 Vorticella, reproduction of, 121, 140 

 Volvox, 52, 120, 122 



Wallace, sexual selection, 9-12 ; nat- 

 ural selection, 24, 278, 279 



Ward, Marshall, on parasitic fungi, 

 212 



Water-fleas, parthenogenesis in, 162 



Weeping willows, 175 



Weismann on fertilization, 151 ; on 

 polar bodies, 99, 100; on use of fer- 

 tilization, 153 ; on parthenogenetic 

 ova, 169-173 ; hydroids, 86, 195, 196 ; 

 alternation of generations, 198; con- 

 tinuity of germ-plasma, 88, 89, 221- 

 223; on organic immortality, 238-241; 

 inheritance of acquired characters, 

 45, 280, 281 ; variation. 282 



Whelk, cannibalism of young, 230 



Winter eggs, 163 



Wolff, reassertion of epigenesis, 81 



Women, subjection, rights, functions 

 of, 247-250 



Worms, hermaphroditism in, 67; asex- 

 ual reproduction, 180-182; alterna- 

 tion of generations, 193 



Yolk glands, 55 



Yolk-sac, 230 



Yung on sex in tadpoles, 36 



Zacharias on male and female ele- 

 ments, 109 ; on asexual multiplica- 

 tion, 208 



Zona pellucida, 97 



Zona radiata, 97 



