1 66 EXPERIMENTAL EVOLUTION LECT. 





forms, we find, as Cornevin has well shown, a marked 

 difference in favour of the former. 



Animals. Skull-capacity. Difference in favour 



of Wild Form. 



Wild Ass of Persia 521 ) 



Domestic 45O j cubic centimetres 71 



Abyssinian Ox 479 \ 



Domestic African Ox ... 432) " " 47 



Moufflon 240 } 



Sheep 122 j> 



Boar (Europe) 190 ) 



Hog 177 f " 



Cochin China Boar 162^ 



Stis mttatus 181 > 



Domestic Chinese Pig ... i5oJ 



Wolf 142! 



Dog ii6/ " 



Jackal 82 "I 



Italian Greyhound 76) " 



Wild Rabbit 9-4^ 



Tame Rabbit 7-5]" " 



At the same time wild animals have heavier brains 

 than the domestic forms. Domestic animals are also 

 heavier and more fleshy, and the tendency towards 

 flesh-production increases with domestication. At 

 the present day our oxen are three times heavier than 

 the same animals, at the same age, four or five centu- 

 ries ago. In France, since the beginning of the 

 century, oxen have more than doubled their weight ; 

 in 1808 the average was 300 kilograms, now it is 700. 

 Domestication also reacts on the length of gestation, 



