chap. xi. preceding and present Chapters^ 315 



^"^^Ttt^^ each successive P-** kj*j 



history have beaten their predecessors in the race for Me, and 

 n n so far, higher in the scale, and their structure has gene- 

 ra iy become more specialised; and this may account for the com- 

 mon belief held by so many palaeontologists, that organisation on 

 Z whole has progressed. Extinct and ancient animals resemble 

 to a certain extent the embryos of the more recent ammals belong- 

 n. to the same classes, and this wonderful fact receives « i simple 

 explanation according to our views. The succession of the same 

 typ s of structure within the same areas during the later geological 

 periods ceases to be mysterious, and is intelligible on the principle 



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 paleontology plainly proclaim, as it seems to 

 me, that species have been produced by ordinary generation : old 

 forms having been supplanted by new and improved forms ot lite, 

 the products of Variation and the Survival of the Fittest. 





