366 



HISTORICAL PALEONTOLOGY. 



roids, so the little banded and cuirassed Armadillos of South 

 America were formerly represented by gigantic species, con- 

 stituting the genus Glyptodon. The Glyptodons (fig. 262) 

 differed 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 Glyptodon clavipes, from the tip of the snout to the end of 

 the tail, was more than nine feet. 



There are no canine or incisor teeth in the Glyptodon, but 

 there are eight molars on each side of each jaw, and the crowns 

 of these are fluted and almost trilobed. The head is covered 

 by a helmet of bony plates, and the trunk was defended by an 

 armour of almost hexagonal bony pieces united by sutures, and 

 exhibiting special patterns of sculpturing in each species. The 

 tail was almost defended by a similar armour, and the vertebrae 

 were mostly fused together so as to form a cylindrical bony 

 rod. In addition to the above-mentioned forms, a number 

 of other Edentate animals have been discovered by the re- 

 searches of M. Lund in the Post-Pliocene deposits of the 

 Brazilian bone-caves. Amongst these are true Ant-eaters, 

 Armadillos, and Sloths, many of them of gigantic size, and all 

 specifically or generically distinct from existing forms. 



Fig. 263. Skull of the Tichorhhie Rhinoceros, the horns being wanting. One-tenth of 

 the natural size. Post-Pliocene deposits of Europe and Asia. 



Passing over the aquatic orders of the Sirenians and Ce- 

 taceans, we come next to the great group of the Hoofed Quad- 

 rupeds, the remains of which are very abundant in Post- 

 Pliocene deposits both in Europe and North America. 

 Amongst the Odd-toed Ungulates the most important are 



