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 paleontologists, 
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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