Chap. IV.] NATURAL SELECTION. I4.7 



they will have taken the places of, and thus extermi- 

 nated not only their parents (A) and (I), but likewise 

 some of the original species which were most nearly re- 

 lated to their parents. Hence very few of the original 

 species will have transmitted ofEspring to the fourteen- 

 thousandth generation. We may suppose that only one, 

 (F), of the two species (E and F) which were least closely 

 related to the other nine original species, has trans- 

 mitted descendants to this late stage of descent. 



The new species in our diagram descended from the 

 original eleven species, will now be fifteen in number. 

 Owing to the divergent tendency of natural selection, 

 the extreme amount of difference in character between 

 species a^* and 2" will be much greater than that be- 

 tween the most distinct of the original eleven species. 

 The new species, moreover, will be allied to each other in 

 a widely different manner. Of the eight descendants 

 from (A) the three marked a^*, g^*, p^*, will be nearly 

 related from having recently branched ofE from a^"; 6", 

 and f^*, from having diverged at an earlier period from 

 a', will be in some degree distinct from the three first- 

 named species; and lastly, 0^*, e^*, and m^*, will be nearly 

 related one to the other, but, from having diverged at 

 the first commencement of the process of modification, 

 will be widely different from the other five species, and 

 may constitute a sub-genus or a distinct genus. 



The six descendants from (I) will form two sub- 

 genera or genera. But as the original species (I) dif- 

 fered largely from (A), standing nearly at the extreme 

 end of the original genus, the six descendants from (I) 

 will, owing to inheritance alone, differ considerably from 

 the eight descendants from (A); the two groups, more- 

 over, are supposed to have gone on diverging in dif- 



