610 LAND MAMMALS IN THE WESTERN HEMISPHERE 



adaptation to their altogether exceptional mode of life, in 

 hanging suspended from the branches of trees ; but, despite this 

 modification, there are so many notable resemblances between 

 the Santa Cruz fGravigrada and the existing Tardigrada as 

 irresistibly to suggest their community of origin, and thus the 

 former served to connect the anteaters, on the one hand, with 

 the tree-sloths, on the other. This must not be construed as 

 meaning that the Miocene tground-sloths were the ancestors 

 of the other suborders, which were probably already in exist- 

 ence as distinct groups, but merely that all three suborders 

 had a common origin, from which the Santa Cruz fGravigrada 

 had departed less than have the sloths and anteaters. 



There is evidence that at least two of the fground-sloth 

 families, the fMegalonychidse and the fMylodontidse, were 

 distinguishable in the Deseado stage, but materials are still 

 lacking to give us any real knowledge of the suborder in that or 

 the more ancient stages. 



Section Loricata. Armoured Edentates 



Suborder Dasypoda. Armadillos 



Armadillos are still an important and characteristic element 

 of the Neotropical fauna, ranging from Texas to Patagonia 

 and showing a considerable variety of structure and appearance. 

 Existing species are all of small or moderate size, and the one 

 which is by far the largest {Priodontes gigas) may somewhat 

 exceed three feet in length, exclusive of the tail, and the smallest 

 (Chlamydophorus truncatus) is hardly more than five inches long. 

 In most armadillos the hair is greatly diminished in quantity 

 and the animal is sheathed in a conspicuous armour of bony 

 scutes, covered with horny plates. There is a head-shield 

 which covers the top of the skull, and the tail is enclosed in a 

 sheath ; the back and sides are protected by the great carapace 

 and the limbs by irregular scutes and scales, leaving only the 

 under side of the body and the inside of the legs uncovered. 



