*' ' i 

 1.56 



M A MM A L I A. 



pendently of the pads with which the solos are pro- 

 vided, gives the animal great, firmness as well as 

 concentration 'on these feet. Some of the family 

 have only three toes upon them, and some have five ; 

 but in the latter the two lateral toes are so little pro- 

 duced that they do not contribute much to the size 

 of the foot. In order to give the requisite firmness, 

 the metatarsal bones are very much produced, and 

 united into a single piece as far as the three principal 

 toes are concerned, thus forming a true canon bone, 

 the same as is found in the feet of animals which are 

 characteristically walkers. The hind feet are thus 

 walking feet of the very best description ; and they 

 are so large and strong in proportion to the fore part 

 of the body of the animal, that they make no bad 

 substitute for all the four feet of animals which use 

 the fore ones as well as the hind for no other purpose 

 but that of walking. In consequence of the elasticity, 

 the jerboa, though comparatively a small animal, can 

 easily jump to the distance of five or six feet ; and it 

 sometimes takes its spring from the toes only, and 

 sometimes from the entire sole of the foot. The lat- 

 ter affords the most vigorous leap, from the velocity 

 with which the rapid unbending of the ankle-joint 

 propels the animal in an upward direction. 



The most characteristic of the leaping animals, 

 however, is the kanguroo. Opportunities now occur 

 at almost every zoological collection, especially those 

 in ample gardens, where the animals can display their 

 natural action much better than they could possibly 

 have done in the old-fashioned places where they 

 had scarcely room to stretch themselves ; but still 

 even in these places the manners of an animal so 

 peculiar in its form and its action, and also in the 

 localities which it inhabits, cannot be seen to their 

 proper advantage. The annexed cut will furnish 

 some idea of it, both in its reposing and in its leaping 

 attitude ; and the reposing one, being nearer in the 

 representation, and therefore on a larger scale, may 



be regarded as a very faithful portrait of the ani- 

 mal. It will be seen "from both figures that the fore 

 legs are exceedingly small ; and that the body of 

 the animal tapers, from the setting on of the hind legs, 

 all the way to the extremity of the nose. But though 

 the fore legs are very small, the extremities of them 



are very well made out. They are each furnished 

 with five toes having a free motion, and armed with 

 claws very strong in proportion to the size of the 

 members themselves, only the two lateral ones are 

 considerably shorter than the rest. The elbow-joints 

 have very free motion, so that the fore arm can per- 

 form a complete revolution, or rather rotation, in the 

 articulation of the radius. The hind legs, though 

 much more produced and powerful than the fore 

 ones, have not the toes on them so well developed. 

 The whole strength of that part of the foot is thrown 

 upon a single bone in the metatarsus, as in the jerboas ; 

 but this bone does not consist of three bones soldered 

 together as in them, it consists of one bone supporting 

 one toe. This bone is remarkable for its size, the 

 toe is very strong, and instead of a claw it is furnished 

 with a true hoof of large dimensions at the extremity. 

 In consequence of this, when the kanguroo springs 

 from the hind feet, it springs from one principal point 

 of support in each, in the same mariner as the single 

 hoofed animals. The feet contain other three toes, 

 much shorter and feebler than the middle one ; so 

 that, though they assist in preserving the balance of 

 the animal when it has the whole length of the tarsus 

 upon the ground, they do not interfere with the free 

 action of the central and powerful toe when the ani- 

 mal leaps. In their bones those three toes make only 

 two ; for the two internal ones are completely united, 

 with the exception of being furnished with two claws, 

 which are not hoofs like those on the middle ones. 

 These lateral claws are long, but they are very feeble 

 as compared with the middle one ; they are meta- 

 tarsal bones, having little more than the one hundred 

 and fiftieth part of its section, and consequently of its 

 strength. There is not so remarkable a difference 

 between the strength of the bones of the toes, in any 

 other known genus of living mammalia ; and indeed 

 in as far as efficiency, when the animal is on the toes, 

 is concerned, they serve little other purpose than the 

 small hoofs, behind the principal ones, with which 

 animals which divide the hoof are generally speaking 

 supplied. This great enlargement of the central toe, 

 and corresponding reduction of the others, is a strik- 

 ing proof that concentration is a most essential requi- 

 site in those extremities from which an animal is to 

 take powerful leaps. The tail of the kanguroo is a 

 still more efficient organ of balancing than that of the 

 jerboas ; and, as will be seen upon looking back at 

 the figures, no other of the mammalia is provided 

 with a tail of equal weight and strength ; in volume 

 it is scarcely less than the entire body, anterior of the 

 portion which is supported directly by the hind legs ; 

 and therefore the animal has its centre of gravity 

 very near the articulations of the thigh bones. The 

 internal structure of the tail indicates as powerful an 

 action in that organ as its form and size indicate 

 weight. The vertebrae of which it is composed are 

 provided with numerous and well developed processes 

 for giving origin and insertion to a vast number of 

 muscles ; and the power of the tail, both in the firm- 

 ness of any position which it assumes, and the rapidity 

 with which it changes from one position to another, 

 gives it very nearly the efficiency of a third foot, whe- 

 ther in supporting the animal, in enabling it to balance 

 itself, or change its direction, or in being used as a 

 weapon against an enemy by which it may be pursued. 

 It is reported indeed that when the kanguroo is chased 

 by the wild dogs of Australia, or by the dogs of the 

 colonists, it does not stand up and take the tremen- 



