BEAVER AND FROG 33 



all, the American monkeys. To a howler, or spider- 

 monkey, its long tail is a swing and a trapeze in 

 its forest gymnasium. Humboldt saw (he says it) 

 a cluster of them all hanging from a tree by one 

 tail, which proceeded from a Sandow in the middle. 

 I should like to see that too. It is worth noting, 

 by the way, that no old-world monkey has attained 

 to this application of its tail. 



Then there is the beaver, whose tail I am con- 

 vinced is a trowel. I know of no naturalist who 

 has mentioned this, but such negative evidence is 

 of little weight. The beaver, as everybody knows, 

 is a builder, who cuts down trees and piles log upon 

 log until he has raised a solid, domed cabin from 

 seven to twenty feet in diameter, which he then 

 plasters over with clay and straw. If he does not 

 turn round and beat the work smooth with his tail, 

 then I require to know for what purpose he carries 

 that broad, heavy, and hard tool behind him. 



How few even among lovers of Nature know why 

 a frog has no tail ! The reason is simply that it 

 used that organ up when it was in want. In early 

 life, as a jolly tadpole, it had a flourishing tail to 

 swim with, and gills for breathing water, and an 

 infantile mouth for taking vegetable nourishment. 

 But when it began to draw near to frog's estate, 

 serious changes were required in its structure to fit 

 it for the life of a land animal. Four tiny legs 

 appeared from under its skin, the gills gave place 

 to air-breathing lungs, and the infant lips to a great, 



