ADAPTATION OF MAMMALS 223 



with long, hooklike claws, and its powers of digging are 

 remarkable. Some are so skillful that they disappear 

 under the ground almost before they can be approached. 

 It would be difficult to imagine an animal more helpless 

 in a tree than the armadillo ; it would fall to the ground 

 at once ; it is not adapted to such a life as are certain 

 mammals. See how the monkey dashes up from limb to 

 limb. It is so thoroughly adapted to it that it has a fifth 

 hand, the prehensile tail, the latter holding it during a 

 swing across and over space. 



Such an animal is at home in the trees, but not more so 

 than the sloth, the queer, mossHke animal that clings to 

 limbs, its body downward, and never or rarely leaves them. 

 Such an animal appears to be a degenerate form which has 

 lost its ability to live a free and wandering life as its 

 gigantic ancestors did ages ago. This animal is a type 

 of inactivity, contrasting sharply with other mammals, like 

 horses, deer, antelopes, greyhounds, and others, which na- 

 ture has adapted for rapid movements. 



Then there are those which can not run, but can make 

 prodigious leaps, as the kangaroo, certain ones having 

 been known to leap over a horse and rider. Singularly, 

 all the kangaroos are found in Australia, a subject in itself 

 of deep interest to the student of nature, suggesting an 

 interesting study as to the origin and geographical distribu- 

 tion of animals. The leaping marsupials have representa- 

 tives, though not pouched, in America in the little jerboa or 

 jumping rat, and there are several jumping mice with long 

 legs which go bounding along in a marvelous fashion. 



In their care of young there is the greatest variety 

 among mammals, a study of intense interest. I had at one 



