HAS EVOLUTION REACHED ITS CxOAL ? Ill 



turn gives origin, as has been abundantly proved, 

 to the birds. Also from the amphibian, in all prob- 

 ability, the mammal is descended. Now let us 

 compare the fore-limbs of the bird and the mammal. 

 In each case we find signs of the specialisation 

 already referred to. In the case of the bird, this 

 has resulted in the allotment of the fore-limbs to 

 the performance of a special type of locomotion — 

 flight. This is well ; but could not the fore-limb 

 have realised higher possibilities ? and are not these 

 now closed to the wing of the bird ? In the case 

 of the mammal, which, in virtue perhaps especially 

 of its reproductive method, has reached a higher 

 plane than the bird, we find various specialisations 

 of the fore-limbs. In the bat, for instance, a web 

 has been formed between the fingers, and the fore- 

 limbs, like those of the bird, have been specialised 

 for flight. Here, also, it would seem that the 

 evolutionary process has ended in a cul-de-sac. 



But, ignoring such exceptions as the bat, and 

 keeping, so to speak, to the mam line of advance, 

 what do we find to be the history of the fore-limbs ? 

 Surely the greatest potentialities open out before a 

 line of evolution which does not involve the sacrifice 

 of one-and-a-half fingers, and the simplification of 

 the rest, as in the bird, nor the permanent attach- 

 ment of the finger-edges to each other, as in the 

 bat, nor the loss of three digits out of five, as in the 

 pig, or of four out of five, as in the horse. Surely 

 the policy of retaining all the fingers, and the inde- 

 pendent mobility of each, will carry furthest the 

 creature that adopts it. This was the policy of the 

 monkey-tribe. 



