4 THE EVOLUTIONIST AT LARGE. 



varieties entirely depends. A gardener may 

 raise a thousand seedlings, and only one or 

 none among them may present a single new 

 and important feature. So a species may 

 wait for a thousand years, or for ever, before 

 its circumstances happen to produce the first 

 step towards some desirable improvement 

 One extra petal may be invaluable to a five- 

 rayed flower as effecting some immense saving 

 of pollen in its fertilisation ; and yet the 

 ' sport ' which shall give it this sixth ray may 

 never occur, or may be trodden down in the 

 mire and destroyed by a passing cow. 



