TRANSMUTABLE. 133 



the fish a creature much below it in the scale, 

 and from which change it would be impossible 

 to conceive anything that could be gained for 

 the benefit of the mammal ! So with the squirrels. 

 Of course the nearer this animal approaches the 

 flying squirrel, the more it assumes the structure 

 of the bird a creature much lower down in the 

 scale than itself! Mr. D. thinks that this might 

 be rendered necessary by the change of climate 

 and vegetation, introducing other competing ro- 

 dents, and thus driving a squirrel into the 

 "necessity" of having, in "myriads of years," a 

 pair of wings to enable it to escape from its 

 enemies. This reasoning sounds so much like 

 downright nonsense, that I must quote Mr. D.'s 

 own words. 



"But it cloes not follow from this fact that the 

 structure of each squirrel is the best, that it is 

 possible to conceive under all natural conditions. 

 Let the climate and vegetation change, and let 

 other competing rodents, or new beasts of prey, 

 immigrate, or old ones become modified, and all 

 analogy would lead us to believe that some at 

 least of the squirrels would decrease in numbers, 

 or become exterminated, unless they also became 

 modified in structure in a corresponding manner." 

 -(Pages 180-1.) 



In the same way the so-called flying lemur 

 might, according to Mr. Darwin, be converted 

 into a bat, an animal which is lower down in 

 the scale; and of what benefit could this be to 

 the flying lemur? Its present power of gliding 



