THE ARGUMENTS PROM CLASSIFICATION. 449 



we consider that this only known cause of similarity, joined 

 with the only known cause of divergence (the influence of 

 conditions), gives us a key to these likenesses obscured by 

 unlikenesses ; we shall see that were there none of those 

 remarkable harmonies above pointed out, the truths of classi- 

 fication would still yield strong support to our conclusion. 



