xviii THK PROBLEM OF UTILITY 393 



Special Cases Discussed. 



The Niata cattle of South America, which have strangely 

 upturned jaws, are said to breed very true and to form a 

 definite well-marked race w^hich, if the character were not 

 injurious but simply indifferent, might lead to the 

 formation of a species defined by this useless specific 

 character. The short-legged Ancon sheep, and the six- 

 toed cats, are other examples of such remarkable ab- 

 normalities or sports which have the curious property of 

 being strongly hereditarj^, and yet, apparently, of never 

 leading to the formation of new species. Almost all 

 students of evolution now admit that " sports " or large 

 and sudden divergencies from the specific type are not the 

 materials from which new species have been formed, the 

 reason being that they are extremely rare occurrences ; 

 and when any such " sport " appeared in a species, the 

 individual presenting it would either be avoided by its 

 fellows and leave no offspring, or by repeated crossings 

 with the normal type the sport would disappear. We 

 may, no doubt, imagine conditions under which a sport of 

 this kind, once appearing in both sexes, might lead to the 

 formation of a breed and ultimately of a species ; but the 

 combination of conditions requisite to bring this about is 

 so improbable that we can only look upon it as a bare 

 possibility. But the question we are discussing is not 

 whether, under certain very rare and exceptional conditions, 

 a few species may possibly be formed which are dis- 

 tinguished only by altogether useless characters, but 

 whether such characters are common in the majority of 

 species and, to use Mr. Romanes' words, exist in 

 " enormous numbers." The case of abnormal sports or 

 monstrosities such as those here referred to can certainly 

 not be adduced as giving any support to this view. 



The next case, that of the Porto Santo rabbits, is held 

 by Mr. Romanes to prove that the constant characters 

 which distinguished them from common rabbits were only 

 results of the action of peculiar conditions on individuals, 

 and were not produced by natural selection. He arrives 



