338 LIFE, IN ITS HIGHER FORMS 



e concludes that the Mylodou — 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 hind- 

 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." i -*-jL v/" 



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 of 

 the well-armed jaws of the higher quadrupeds ; for they are 



