190 SPECIFIC CHARACTERS [Chap. V. 



blue species varying into red, or conversely; but if all 

 the species had blue flowers, the colour would become a 

 generic character, and its variation would be a more 

 unusual circumstance. I have chosen this example be- 

 cause the explanation which most naturalists would 

 advance is not here applicable, namely, that specific 

 characters are more variable than generic, because they 

 are taken from parts of less physiological importance 

 than those commonly used for classing genera. I be- 

 lieve this explanation is partly, yet only indirectly, 

 true; I shall, however, have to return to this point in 

 the chapter on Classification. It would be almost su- 

 perfluous to adduce evidence in support of the state- 

 ment, that ordinary speciflc characters are more variable 

 than generic; but with respect to important characters, 

 I have repeatedly noticed in works on natural history, 

 that when an author remarks with surprise that some 

 important organ or part, which is generally very con- 

 stant throughout a large group of species, differs con- 

 siderably in closely-allied species, it is often variable 

 in the individuals of the same species. And this fact 

 shows that a character, which is generally of generic 

 value, when it sinks in value and becomes only of spe- 

 cific value, often becomes variable, though its physio- 

 logical importance may remain the same. Something 

 of the same kind applies to monstrosities: at least Is. 

 Geoffroy St. Hilaire apparently entertains no doubt, 

 that the more an organ normally differs in the different 

 species of the same group, the more subject it is to 

 anomalies in the individuals. 



On the ordinary view of each species having been 

 independently created, why should that part of the 

 structure, which differs from the same part in other 



