63 



length, and from the increased strength and the inequality of the claws, 

 especially the disproportionately large size of that weapon of the 

 middle digit, that the fore-foot of the ivlegatherium was occasionally 

 applied by the short and strong fore-limb in the act of digging; but 

 its analogy to that of the Ant-eaters teaches that the fossorial actions 

 were limited to the removal of the surface-soil, in order to expose 

 something there concealed, and not for the purpose of burrowing. 

 Such an instrument would be equally effective in the disturbance of 

 roots and ants ; it is, however, still bettei' adapted for grasping than 

 for delving. But to whatever task the partially unguiculate hand of 

 the Megatherium might have been applied, the bones of the wrist, 

 fore-arm, arm and shoulder, attest the prodigious force which would 

 be brought to bear upon its execution. The general organization of 

 the anterior extremity of the ^Jegatherium is incompatible with its 

 being a strictly scansorial or exclusively fossorial animal, and its 

 teeth and jaws decidedly negative the idea of its having fed upon 

 insects ; the two extremes in regard to the length of the jaws are 

 presented by the phyllophagous and rayrmecophagous members of 

 the Edentate order, and the ^Megatherium in the shortness of its 

 face agrees with the Sloths. 



Proceeding then to other parts of the skeleton for the solution of 

 the question as to how the Megatherium obtained its leafy food, the 

 author remarks that the pelvis and hind limbs of the strictly bur- 

 rowing animals, e. g. the Mole, are remarkably slender and feeble, 

 and that they offer no notable development in the Eabbit, the Oryc- 

 terope, or other less powerful excavators. In the climbing animals, 

 as e.g. the Sloth and Orang, the hind-legs are much shorter than 

 the fore-legs, and even in those Quadrumana in which the pre- 

 hensile tail is superadded to the sacrum, the pelvis is not remarkable 

 for its size or the expansion of the iliac bones. But in the Mega- 

 therium the extraordinary size and massive proportions of the pelvis 

 and hind limbs arrest the attention of the least curious beholder, and 

 become eminently suggestive to the physiologist of the peculiar 

 powers and actions of the animal. The enormous pelvis was the 

 centre whence muscular masses of unwonted force diverged to act 

 upon the trunk, the tail, and the hind legs, and also by the ' latis- 

 simus dorsi ' on the fore-limbs. The fore-foot being adapted for 

 scratching as well as for grasping, may have been employed in 

 removing the earth from the roots of the tree and detaching them 

 from the soil. The fore-limbs being well adapted for grasping the 

 trunk of a tree, the forces concentrated upon them from the broad 

 posterior basis of the body may have co-operated with them in the 

 labour, to which they are so amply adapted, of uprooting and pro- 

 strating the tree. To give due resistance and stability to the pelvis, 

 the bones of the hind-legs are as extraordinarily developed, and the 

 strong and powerful tail must have concurred with the two hind-legs 

 in forming a tripod as a firm foundation for the massive pelvis, and 

 affording adequate resistance to the forces acting from and upon 

 that great osseous centre. The large processes and capacious spinal 

 canal indicate the strength of the muscles which surrounded the tail, 



