in THE SERVICE OF TAILS 77 



prehensibility in its tip, similar to that in the toes 

 of perching-birds, which close tightly around a 

 twig, without any effort on the bird's part, simply 

 as the result of the pressure of its weight. 



Charles Waterton points out that this faculty is 

 of manifest advantage to the animal, either when 

 sitting in repose on the branch of a tree or during 

 its journey onward through the gloomy recesses 

 of the wilderness. "You may see this monkey," 

 he writes, " catching hold of the branches with 

 its hands, and at the same time twisting its tail 

 around one of them, as if in want of additional 

 support; and this prehensile tail is sufficiently 

 strong to hold the animal in its place, even when 

 all its four limbs are detached from the tree, so 

 that it can swing to and fro, and amuse itself, 

 solely through the instrumentality of its prehen- 

 sile tail which, by the way, would be of no man- 

 ner of use to it did accident or misfortune force 

 the monkey to take up a temporary abode upon 

 the ground. For several inches from its extremity, 

 by nature and by constant use, this tail has as- 

 sumed somewhat the appearance of the inside of 

 a man's finger, entirely denuded of hair or fur 

 underneath, but not so on the upper part." 



Prehensibility is equally well developed in the 

 naked, rat-like tail of the 'possum of our Northern 

 woods, and to a less extent in the manis; in the 

 Old World, or true, chameleon ; in the tips of the 

 tails of tree-clinging serpents ; and among fishes 



