56 RESEMBLE VhUtBTIES. 



other species apparently have restricted ranges. In all 

 these respects the species of large genera present a strong 

 analogy with varieties. And we can clearly understand 

 these analogies, if species once existed as varieties, and 

 thus originated; whereas, these analogies are utterly inex- 

 plicable if species are independent creations. 



We have also seen that it is the most flourishing or domi- 

 nant species of the larger genera within each class which 

 on an average yield the greatest number of varieties; and 

 varieties, as we shall hereafter see, tend to become con- 

 verted into new and distinct species. Thus the larger 

 genera tend to become larger; and throughout nature the 

 forms of life which are now dominant tend to become still 

 more dominant by leaving many modified and dominant 

 descendants. But, by steps hereafter to be explained, the 

 larger genera also tend to break up into smaller genera. 

 And thus, the forms of life tb';oughout the universe be- 

 come divided into groups subordinate to groups. 



