The Making of Species 



MUTATIONS AMONG ANIMALS 



Some instances of great and sudden variation 

 in domesticated animals have become classical, 

 and been detailed in almost every work on 

 evolution. These are, firstly, the celebrated 

 hornless Paraguay cattle. This hornless breed, 

 or rather the ancestor of the breed, arose quite 

 suddenly. 



Many domestic horned breeds of animals, 

 especially sheep and goats, throw off hornless 

 sports. Were a hornless breed of buffalo found 

 in nature, it would undoubtedly be ranked a 

 new species, and the Wallaceians would doubt- 

 less exercise much ingenuity in explaining how 

 natural selection had brought about the gradual 

 disappearance of the horns ; and palaeontologists, 

 being baffled in their search for intermediaries 

 between the hornless species and their horned 

 ancestors, would complain of the imperfection of 

 the geological record. 



It may, perhaps, be argued that this hornless 

 mutation was a direct result of the unnatural 

 conditions to which the Paraguay cattle were 

 subjected, it may be asserted that since there 

 are no species of hornless cattle in nature, such 

 mutations have never occurred under natural 

 conditions, and hence the Paraguay cattle prove 

 nothing. As a matter of fact, we know that in 

 nature a great many mutations occur which are 



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