128 SUMMARY OP CHAPTERS. [Chap. XL 



The inhabitants of the world at each successive 

 period in its history have beaten their predecessors in 

 the race for life, and are, in so far, higher in the scale, 

 and their structure has generally become more special- 

 ised; and this may account for the common belief held 

 by so many palaeontologists, that organisation on the 

 whole has progressed. Extinct and ancient animals re- 

 semble to a certain extent the embryos of the more re- 

 cent animals belonging to the same classes, and this 

 wonderful fact receives a simple explanation according 

 to our views. The succession of the same types of 

 structure within the same areas during the later geologi- 

 cal periods ceases to be mysterious, and is intelligible 

 on the principle of inheritance. 



If then the geological record be as imperfect as many 

 believe, and it may at least be asserted that the record 

 cannot be proved to be much more perfect, the main 

 objections to the theory of natural selection are greatly 

 diminished or disappear. On the other hand, all the 

 chief laws of palaeontology plainly proclaim, as it seems 

 to me, that species have been produced by ordinary gen- 

 eration: old forms having been supplanted by new and 

 improved forms of life, the products of Variation and 

 the Survival of the Fittest. 



