OF EVOLUTION. 17 



amphibian is, in truth, an animal that binds the 

 three groups together. 



If we now ask ourselves what are the relative 

 positions of these three groups, the answer is a 

 very simple one. The amphibians are obviously 

 higher than the fishes, since they pass from, or 

 through, a fish stage to maturity ; developing in 

 the direction of the reptile, they naturally point 

 to the latter as the superiors in the scale 

 of organization. Recognizing this position, what 

 is the nature of the geological history that they 

 would be likely to tell? That the fishes appeared 

 first, that the amphibians came next, and that 

 these were followed by the reptiles, just as we 

 have seen it actually to have been the case. It 

 is a remarkable fact, and one most confirmatory of 

 the doctrine of evolution, that the history of the 

 individual development of an animal frequently 

 repeats the development of the broad group which it 

 represents. But geological evidence is not entirely 

 satisfied with the evidence of succession, corres- 

 ponding to the law of development, which I have 



(2) 



