80 



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 Megatherium 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 myrmecophagous members 

 of the order Bruta, 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, it may be remarked that the pelvis and 

 hind limbs of the strictly burrowing animal, e. g. the Mole, are remarkably slender and 

 feeble, and they offer no notable development in the Rabbit, the Orycterope, or other less 

 powerful excavators. In the climbing animals, as, e. g., the Sloths and Orangs, the hind 

 legs are much shorter than the fore legs ; and even in those Quadrumana in which the 

 prehensile tail is superadded to the sacrum, the pelvis is not remarkable for its size or 

 the expansion of its iliac bones. But, in the Megatherium, the extraordinary bulk and 

 massive proportions of the pelvis and hind limbs arrest the attention of the least curious 

 beholder, and become to the physiologist eminently suggestive 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 ' latissimus 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 : but the hind foot, which, like a 

 pickaxe, had but one strong perforating and digging pointed weapon, was more pro- 

 bably the instrument mainly employed in removing the earth from the ramifications of 

 the root The fore limbs, terminated each by three claws, appear to have been more 

 especially adapted for grasping the trunk of a tree ; and the forces concentrated upon 

 them from the broad posterior basis of the body must have cooperated with them in the 

 labour, for which they are so amply organized, of uprooting and prostrating the tree. 

 To give due resistance and stability to the pelvis, the bones of the hind legs are extra- 

 ordinarily and massively developed, and the strong and powerful tail must have con- 

 curred with the two hind legs in forming a tripod, as a firm foundation for the vast 

 pelvis, thus providing adequate resistance to the forces acting and re-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, and the vast mass of nervous 

 fibre from which those muscles derived their energy. The natural co-adaptation of the 

 articular surfaces shows that the ordinary inflection of the end of the tail was backward, 

 as in a Cauda fulciens, not forward, as in a cauda preliensilis. Dr. Lund's hypothesis, 

 therefore, that the Megatherium was a climber and had a prehensile tail, is destroyed 

 by the now known structure of that part. 



