INDEX OF SUBJECTS 



255 



Tomato, number of cells in fruit. . 46 



Transitional populations, rarity of, 165 



an example 178 



Tropaeolum, sterile anthers in. . . . 238 



Trypanosomes, variation in 216 



Tusk, of Elephant, segmented. ... 38 



of Narwhal 44 



Twinning 41, 44, 71 



heredity of 45 



in organs 46 



Uria troile, variety of 150 



Vanessa urticae, effects of tempera- 

 ture 191 



Variation, a medley of phenomena, 



14. IS 



sporadic 131, 134 



and locality 118 



Variation, Causes of gi 



-7. I31i »X3 



Substantive and meristic 83 



Veronica, specific difference in. . . . 10 

 rimental modification 211 



intermedi. <ies... 17 

 Vertebuu-. dh ision in | 



homologies of 



Vespa, specific difference in 23 



Vortex, living organism compared 



with 40 



Wave-motion compared with n 

 tition of parts 62, I 



Wheat, cumulative factors in 116 



climatic experiments on 195 



Woodpecker 235 



Zebra, pattern of stripes compared 

 with ripples 38 



