DISTRIBUTION OF MAMMALIA IN TIME. 643 



and in Africa occurs the Edentate genus Orycteropus. South 

 America, however, is the metropolis of the Edentata, the order 

 being there represented by the Sloths, the Armadillos, and the 

 true Ant-eaters. It is also in South America that by far the 

 greater number of extinct Edentates have been found ; and, as 

 in the case of the Australian Marsupials, the fossil forms are 

 gigantic in size compared with their living representatives. 



Fig. 275. Megatherium. From the Upper Tertiaries of South America (Pleistocene). 



The Sloths (Bradypodidce) of the present day were repre- 

 sented in Post-tertiary times by a group of gigantic forms 

 referable to the genera Mylodon, Megalonyx, and Megatherium. 

 Of these, Mylodon attained a length of eleven feet, and Mega- 

 therium (fig. 275) was eighteen feet in length, with bones as 

 massive, or more so, than the Elephant. 



In the same way the little banded Armadillos of South 

 America were formerly represented by gigantic species, on- 



Fig. 276. Glyptodon clavipes. Pleistocene deposits of South America. 



stituting the genus Glyptodon. The Glyptodons (fig. 276) dif- 

 fered from the living Armadillos in having no bands in their 

 armour, so that they must have been unable to roll themselves 

 up. It is rare at the present day to meet with any Armadillo 

 over two or three feet in length ; but the length of the Glypto- 



