the Megatherium. 355 



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 Megatherium the extraordinary size and massive 

 proportions of the pelvis and hind limbs arrest the attention 

 of the least curious beholder, and become eminently sug- 

 gestive 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 " latissimr^ 

 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 detach- 

 ing 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 prostrating 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 pro- 

 cesses 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 backwards 

 as in a cauda fulciens^ not forwards as in a cauda prehensilis. 

 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. 



But viewing, as the Professor conceives, the pelvis of the 

 Megatherium as being the fixed centre towards which the two 

 legs and fore part of the body were drawn in the gigantic 

 leaf-eater's efforts to uprend the tree that bore its suste- 

 nance, the colossal proportions of its hind extremities and 

 tail lose all their anomaly, and appear in just harmony with 



