392 LOUIS AGASSIZ. 



cies reputed identical in various successive de- 

 posits, — species which are always quoted in 

 favor of a transition, however indirect, from 

 one group of species to another, — and I have 

 always found marked specific differences be- 

 tween them. In a few weeks I will send you 

 a paper which I have just printed on this sub- 

 ject, where it seems to me this view is very 

 satisfactorily proved. The idea of a procrea- 

 tion of new species by preceding ones is a gra- 

 tuitous supposition opposed to all sound phys- 

 iological notions. And yet it is true that, 

 taken as a whole, there is a gradation in the 

 organized beings of successive geological for- 

 mations, and that the end and aim of this 

 development is the appearance of man. But 

 this serial connection of all successive creat- 

 ures is not material ; taken singly these groups 

 of species show no relation through interme- 

 diate forms genetically derived one from the 

 other. The connection between them becomes 

 evident only when they are considered as a 

 whole emanating from a creative power, the 

 author of them all. To your special questions 

 I may now very briefly reply. 



Have fishes descended from a primitive 

 type? So far am I from thinking this pos- 

 sible, that I do not believe there is a single 



