INDEX 



,21 



Unit characters, 98; misplaced, 138; 



species composed of, 98 

 Unused materials, 30 

 Urus, 225 



Variability, coefficient of, 112 ; eco- 

 nomic significance of, 44 ; from 

 type, 109; in a single character, 47; 

 in milk production, 40; in pigeons, 

 93-95; of a single character, 105 



Variation of domesticated races, 1 1 



Vetch, 264 



Vigor, significance of, 69 



Wart hog, 233 



Way of the wild, 50 



Weapons, defensive, significance of, 7 1 



Weeds, 298 



Weeping habit, 151 



Wheat of lake dwellers, 265 ; ori- 

 gin of, 242 ; strains of, 243 



Wild ass, 22 



Wild boar, 16, 231 



Wild grape, 15* 



Wild lettuce, 299 



Wild white cattle, 225 



Wolf, contrasted with dog, 22 ; domes- 

 tication of, 13*, 21; of South Amer- 

 ica, 208 



Women, primitive, hard lot of, 27 



Yak, 221* 

 Zebra, 217 



