Mutations among Mammals 



not perpetuated because not beneficial to the 

 species. A hornless individual in the wild 

 state would stand but little chance in fighting for 

 females against his horned brethren. We must 

 keep clearly in mind that the theory of mutation 

 does not seek to abolish natural selection; it 

 merely affords that force something substantial 

 to work upon. 



The second classical example of a leap taken 

 by nature is furnished by the Franqueiro breed 

 of long-horned cattle in Brazil. These furnish 

 us with an example of a mutation in the other 

 direction. Then there is the Niata or bull-dog 

 breed of cattle, which are also South American. 

 These instances would seem to indicate that 

 cattle are what De Vries would call " in a mutat- 

 ing state " in that part of the world. 



The other classical examples of great and 

 sudden variations are the Ancon sheep of Massa- 

 chusetts, the Mauchamp breed of Merino sheep, 

 the tufted turkeys, and the long-haired race of 

 guinea-pigs. 



The " wonder horses," whose manes and tails 

 grow to an extraordinary length, so as to trail 

 on the ground, may perhaps be cited as a race 

 which originated in a sudden mutation. They 

 are all descendants of a single individual, 

 Linus I., whose mane and tail were respectively 

 eighteen and twenty-one feet long. But in this 

 case it is important to note that the parents and 



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