PEOEESSOE OWEN ON THE MEGATICBEIUM. 
827 
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 gi've 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 
articulai surfaces shows that the ordinary infiection of the end of the tail was backward, 
as in a caiida fulciens, not forward, as in a cauda preTiensilis. Dr. Lui^d’s hypothesis, 
therefore, that the Megatherium wns a climber and had a prehensile tail, is destroyed 
by the now known structure of that part. 
But viewing the pelvis of the Megatherium as being the fixed centre towards which 
the foie legs and fore part of the body were drawn in the gigantic leaf-eater’s efibrts to 
uprend the tree that bore its sustenance, the colossal proportions of its hind extremities 
and tail lose all their anomaly, and appear in just harmony with the robust claviculate 
and unguiculate fore limbs with which they combined their forces in the Herculean 
labour. 
Finally, with reference to the hypothesis of the German authors and artists* of the. 
gradual degeneiation of the ancient Megatherioids of South America into the modern 
Sloths, it may be admitted that the general results of the labours of the anatomist in 
the restoration of extinct species, viewed in relation to their existing representatives of 
the different continents and islands, have been such as might naturally suggest the idea 
that the races of animals had deteriorated in point of size. Thus the palmated Megaceros 
is contrasted, by its superior bulk, with the Fallow-deer, and the great Cave-bear with the 
actual Brown Bear of Europe. The huge Diprotodon and Nototherium afford a similar 
contrast with the Kangaroos and Koalas of Australia, as do the towering Dinornis and 
Palapteryx with the small Apteryx of New Zealand. But the comparatively diminutive 
aboriginal animals of South America, Australia, and New Zealand, which are the nearest 
allies of the gigantic extinct species respectively characteristic of such tracts of dry land, 
are specifically distinct, and usually by characters so well marked as to require a sub- 
generic division, and such as no known outward influences have been observed to pro^ 
duce by progressive alteration of structure. Moreover, as in England, for example, our 
Moles, Water-voles, Weasels, Foxes, and Badgers, are of the same species as those that 
coexisted with the Mammoth, Tichorhine Bhinoceros, Cave Hysena, Bear, &c. ; so likewise 
the remains of small Sloths and Armadillos are found associated with the Megatherium 
* Paxdeb and D’ Alton, loc. cit. 
5q2 
