ORG A NIC EVOL UTION. 33 



or devil-fish belongs to a widely different class 

 of animals from a true fish, and yet its eye, in 

 general appearance, looks wonderfully like the 

 eye of a true fish. Now, Mr. Mivart pointed to 

 this fact as a great difficulty in the way of the 

 theory of evolution by natural selection, because 

 it must clearly be a most improbable thing that 

 so complicated a structure as the eye of a fish 

 should happen to be arrived at through each of 

 two totally different lines of descent. And this 

 difficulty would, indeed, be almost fatal to the 

 theory of evolution by natural selection, if the ap- 

 parent similarity were a real one. Unfortunately 

 for the objection, however, Mr. Darwin clearly 

 showed, in his reply, that in no. one anatomical 

 feature of typical importance do the two structures 

 resemble one another ; so that in point of fact 

 the two organs do not resemble one another in 

 any particular further than it is necessary that 

 they should, if both are to serve as organs of 



D 



