Survival of the Fittest. 443 



occurred in nature and have been preserved and accumulated 

 by Natural Selection, and not in the ordinary view of inde- 

 pendent creation, we can understand why the specific charac- 

 ters, or those by which the species of the same genus differ 

 from each other, should be more variable than the generic 

 characters in which they all agree. Inexplicable as is the 

 occasional appearance of stripes on the shoulders and legs of 

 the different equine species and their hybrids on the theory 

 of creation, yet how simply is the fact explained if we believe 

 that they are all descended from a striped progenitor just as 

 the different domestic breeds of pigeons are descended from 

 the blue and barred rock-pigeons. Why, for example, 

 should the color of a flower be more likely to vary in any 

 one species of a genus, if the other species, supposed to have 

 been created independently, have differently-colored flowers, 

 than if all the species of the genus have the same colored 

 flowers ? On the theory that species are only well-marked 

 varieties, of which the characters have become in a high 

 degree permanent, the fact is intelligible, for they have 

 already varied in certain characters since they branched off 

 from a common progenitor, and by these characters they 

 have come to be specifically distinct from each other. There- 

 fore, these same characters would be more likely again to 

 vary than the generic characters which have been inherited 

 without change for an enormous period of time. 



Upon the theory of Natural Selection, or the Survival of 

 the Fittest, with its contingencies of extinction and diver- 

 gence of character, we can see how it is that all past and 

 present organic beings can be arranged within a few classes, 

 in groups subordinate to groups, and with the extinct groups 

 often falling in between the recent groups. We can see how 

 it is that the mutual affinities of the forms within each class 

 are so complex and diversified, and only adaptive characters, 

 though of superior importance to the beings, are of scarcely 

 any significance in classification, while those derived from 

 rudimentary parts, though of no recognized service, are often 



