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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