ggg LIFE, IN ITS HIGHER FORMS. 
He concludes that the Mylodon — a leaf-eater, like its 
modern cousins the Sloths of Brazil— having partly exposed 
the roots of a living tree, by means of its powerful front 
claws adapted for digging, was accustomed to rear itself 
up on the broad tripod formed by its own immense hmd- 
feet and its strong tail, and embracing the trunk of the tree 
with its fore-feet, put forth all its mighty strength in striv- 
ing to overthrow it. “ The tree being thus partly under- 
mined, and firmly grappled with the muscles of the body, 
the pelvis, and the hind limbs, animated by the nervous 
influence of the unusually large spinal cord, would combine 
their forces with those of the anterior members in the 
efforts at prostration. And now let us picture to ourselves 
the massive frame of the Megatherium, convulsed with the 
mighty wrestling, every vibrating fibre re-acting upon its 
bony attachment with a force which the strong and sharp 
crests and apophyses loudly bespeak : extraordinary must 
have been the strength and proportions of that tree, which, 
rocked to and fro, to right and left, in such an embrace, 
could long withstand the efforts of its ponderous as- 
sailant.” 
The populous Class of mostly small quadrupeds, known 
as Rodentia, or Gnawers — of which, the Rabbit and the Rat 
are familiar examples— rise but little, in the scale of orga- 
nization, above the Edentata. They display but little 
intelligence, have few means of defence, are timid and 
feeble, and as they are the prey of many enemies, they are 
preserved from extermination only by their amazing ferti- 
lity. Their peculiar dentition is, moreover, intermediate 
between the toothless condition of the Ant-bears and that oi 
the well-armed jaws of the higher quadrupeds ; for they are 
