50 THE GENESIS OF SPECIES. [CHAP. 



tion had appeared at once, if in the hypothetically fortu- 

 nate common ancestor of these fishes an eye had suddenly 

 become thus transferred, then the perpetuation of such 

 a transformation by the action of " Natural Selection " is 

 conceivable enough. Such sudden changes, however, are 

 not those favored by the Darwinian theory, and indeed the 

 accidental occurrence of such a spontaneous transformation is 

 hardly conceivable. But if this is not so, if the transit was 

 gradual, then how such transit of one eye a minute fraction 

 of the journey toward the other side of the head could bene- 

 fit the individual is indeed far from clear. It seems, even, 

 that such an incipient transformation must rather have been 

 injurious. Another point with regard to these flat-fishes is 

 that they appear to be in all probability of recent origin 

 i. e., geologically speaking. There is, of course, no great 

 stress to be laid on the mere absence of their remains from 

 the secondary strata, nevertheless that absence is notewor- 

 thy, seeing that existing fish families, e. g., sharks (Squa- 

 lidse), have been found abundantly, even dow^n so far as 

 the carboniferous rocks, and traces of them in the Upper 

 Silurian. 



Another difficulty seems to be the first formation of the 

 limbs of the higher animals. The lowest Vertebrata 20 are 

 perfectly limbless, and if, as most Darwinians would prob- 

 ably assume, the primeval vertebrate creature was also 

 apodal, how are the preservation and development of the 

 first rudiments of limbs to be accounted for such rudi- 

 ments being, on the hypothesis in question, infinitesimal 

 and functionless ? 



In reply to this, it has been suggested that a mere flat- 

 tening of the end of the body has been useful, such, e. g., as 



20 The term " Vertebrata " denotes that large group of animals which 

 are characterized by the possession of a spinal column, commonly known 

 as the " backbone." Such animals are ourselves, together with ah 1 beasts, 

 birds, reptiles, frogs, toads, and efts, and also fishes. 



