SUBJECT INDEX. 



415 



Variations, swamped by inter- 

 crossing, 57, 58; relation of, 

 to variable environment, 197, 

 199; and modifications, 223; 

 adaptive, 371; definite and 

 indefinite, 371 



Varieties, sterility between, 69 

 Variety, replacing type form, 91 

 Ventricosity, variability of, in 



periwinkle, 206, 215 

 Vetch, effect of water on, 265 

 Volume of water, effect of, on 

 growth of snail, 302; of tad- 

 pole, 306; of Daphnia, 308 



W 



Waltzing mice, reversion in, 142 

 Warmth, effect of, on Lepidop- 



tera, 233 

 Weight, human, variability of, 



205 

 Willow, interchange of root and 



stem in, 376 

 Wolf, variation in, 328 

 Woman, variability of, 205 



Zebras, crosses with, 168 



THB END. 



