296 DENTAL SYSTEM OF THE MEGATHERIUM. 



In all essential cliaracters the teeth of the megatherium 

 repeat, on a magnified scale, the dental peculiarities of the 

 sloth; and since, from a similarity of the form, number, 

 kinds, and structure of teeth, a similarity of food is to be 

 inferred, it may be concluded that the leaves and soft 

 succulent sprouts of trees formed the staple diet of the 

 megatherium, and of the cognate and contemporary me- 

 galonyx and mylodon, as of the existing sloths. The 

 enormous claws of those great extinct sloth-like quadru- 

 peds, to judge by the fossorial (digging and scratching) 

 character of the powerful mechanism of the limbs that 

 worked them, were employed, not, as in the sloths, to 

 carry the animal to its food, but to bring the food within 

 the reach of the animal, by uprooting the trees on which 

 it grew. 



In the remains of the megatherium, we have evidence 

 of the framework of a quadruped equal to the task of un- 

 dermining and tearing down the largest trees in a tro- 

 pical forest. In the latter operation, it is obvious that 

 the immediate application of the anterior extremities to 

 the trunk of the tree would demand a corresponding 

 fulcrum to be effectual; and it is the necessity for an ad- 

 equate basis of support and resistance to such an applica- 

 tion of the fore-extremities which gives the explanation 

 of the seemingly anomalous development of the pelvis, 

 tail, and hinder extremities of the megatherium and its 

 extinct allies. No wonder, therefore, that their type of 

 structure should be so peculiar; for, where shall we now 

 find quadrupeds equal, like them, to the habitual task of 

 uprooting trees for food. 



