PEOMSOE OWEN ON THE IMEGATHEEIOI. 
826 
the hypothesis of Pandee and D’Alton*, that the Megatherinni was a burrowing 
animal. 
The same structure equally shows that it was not, as Dr. LuNDf supposes, a scansonal 
quadruped ; for, in the degree in which the foot departs from the structure of that of 
the existing Sloths, it is unfitted for climbing ; and the outer digit is modified, after the 
ungulate type, for the exclusive office of supporting the body in ordinary terrestnal pro- 
gression. It may be inferred from the diminished curvatui-e and length, and from the 
increased strength and the inequality of the claws, especiaUy the disproportionately 
large size of that weapon of the middle digit, that the fore foot of the Megatherium was 
occasionally applied by the short and strong fore limb in the^ act of digging ; but its 
analogy to that of the Anteaters 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 equahy effective in the dis- 
turbance of roots and of ants; it is, however, still better adapted for grasping than for 
delving. But to whatever task the partially unguiculate hand of the Megathenum 
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 m regard to the 
length of the jaws are presented by the phyllophagous and mpmecophagous 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 Babbit, the Orycterope, or otlier less 
powerful excavators. In the climbing animals, as, e. </., the Sloths and Oraugs, the hmd 
legs are much shorter than the forelegs; and even in those Quadriimana in uhich 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 extraordinai-y 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 beuig adapted for 
scratching as well as for grasping, may have been employed in removing the eai-th Irom 
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, nas moie pio- 
* Das Eiesen-EaultHer, &c. fol. 1821, p. 16. 
t BHk paa Brasiliens Dyreverden for sidste Jordomyseltning, af Dr. Luxd, 4t.o. Kjobeubain, 1S3S, p. -E 
