EDENTATA. 415 



which attained a length of eighteen feet, with bones as mas- 

 sive as, or more so than, those of the Elephant. The jaws are 

 destitute of canine and incisor teeth, but there are five upper 

 and four lower molars on each side. All the molars have the 

 form of quadrangular prisms, the crowns of which are furnished 

 with well-marked transverse ridges : and they grew from per- 

 manent pulps. The limbs are extremely massive, and the 

 pectoral arch has a clavicle. The digits are very large and 

 strong, and some of them are furnished with well-developed 

 claws. The tail is enormously thick. Unlike the living 

 Sloths, Megatherium must have been terrestrial in its habits, 

 and must have lived upon the foliage of trees which it up- 

 rooted for itself. 



The genus Mylodon comprises large Sloth-like animals, of 

 which the best known is the Mylodon robustus (fig. 344). In 

 its size, Mylodon robustus was smaller than the Megatherium, 

 but it reached a length of eleven feet. In many respects 



Fig. 344. Skeleton of Mylodon robustus. Post-Pliocene, South America. 



Mylodon is very like Megatherium, and the number of the 

 teeth is the same viz., five upper and four lower molars on 

 each side. The crowns of the molars, however, were flat, 

 instead of being ridged. The fore -feet are pentadacty- 



