4 g TYPES OF ANIMAL LIFE 



fore limb, and because the "great toe" is in them 

 reduced to a small tubercle. In other respects also they 

 present an exaggeration of characters before noticed as 

 existing in the phalangers. Thus, their second and third 

 toes are very minute and bound together by skin to the 

 very claws, while the other two toes are exaggerated in 

 size, especially the fourth toe. 



We must now return to the consideration of those 

 Australian mammals, the kangaroos animals which most 

 of our readers have probably seen in confinement, or else 

 know by report to be most expert and prodigious leapers. 

 Some of them are very large animals, as bulky as deer, and 

 rapidity of locomotion is especially necessary for a large 

 animal which inhabits a country subject to such severe and 

 widely extended droughts as is Australia. The herbivo- 

 rous hoofed beasts which were till recently so numerous in 

 the plains of southern Africa the antelopes are also 

 capable of very rapid locomotion. In the antelopes, how- 

 ever, as in all hoofed beasts, all the four limbs (front as 

 well as hind) are exclusively used for locomotion. But in 

 the kangaroos we have animals which require to^ use 

 their front limbs for purposes of more or less delicate 

 manipulation, with respect to the economy of the 

 " pouch." Accordingly, for such creatures to be able to 

 inhabit such a country, the hind limbs must by 

 themselves answer the purpose of both the front and 

 hind limbs of deer and antelopes. But the kangaroo's 

 limbs are quite admirably suited to its needs. The front 

 pair serve as prehensile manipulating organs, while the 

 hind pair amply suffice to carry the animal over great 

 distances and rapidly traverse wide, arid plains in pur- 

 suit of rare and distant water. This harmony between 

 structure, habit, and climate was long ago pointed out 

 by Sir Richard Owen. 



