Cuap. XVIII. Mammals — Summary. 555 



form of inheritance which has prevailed. Finally, with quad- 

 rupeds the contest between the individuals of the same sex, 

 whether peaceful or bloody, has, with the rarest exceptions, 

 been confined to the males ; so that the latter have been modified 

 through sexual selection, far more commonly than the females, 

 either for fighting with each other or for alluring the opposite 

 aes, 



