612 LAND MAMMALS IN THE WESTERN HEMISPHERE 



(ilium) of the hip-bone is narrow, v^y different from the 

 broad plate of the fGravigrada. The humerus has prominent 

 deltoid and supinator ridges and an epicondylar foramen, and 

 the femur has the third trochanter. Though the fore-arm 

 bones are separate, the radius has no freedom of rotation ; tibia 

 and fibula are coossified at both ends. 



In the hind foot there is no great variety of character; it 

 is five-toed and usually has claws, but may have broad, flat 

 nails {e.g. Priodontes), but the manus, which is a burrowing 

 organ, displays different degrees of specialization, which is 

 carried farthest in the Giant Armadillo (Priodontes) . Tabu has 

 the fore foot of quite different type. The armadillos feed 

 chiefly upon insects and worms, but they are omnivorous and 

 eat roots and carrion and sometimes even capture and devour 

 small rodents and lizards. 



As in the case of the fground-sloths, the fossil armadillos 

 so far available are insufficient for tracing the history of the 

 various phyla, or for doing more than making a very brief 

 sketch of the? development of the suborder as a whole. Nearly 

 all of the modern genera have been foimd in the Pleistocene to- 

 gether with several that are extinct, some of the latter of very 

 large size. One of these, \Eutatus, had a carapace without 

 bucklers and made up of 33 movable, transverse bands. 

 Another, ^Chlamydotherium, as large as a rhinoceros and the 

 largest known armadillo, had anterior and posterior bucklers, 

 with several movable bands between; it was especially char- 

 acterized by the teeth, which were divided by a vertical groove 

 into pillars or lobes, thus approximating the teeth of the tglyp- 

 todonts. The genus went far back into the Pliocene, and the 

 more ancient species were successively smaller. 



Though remains of armadillos abound in the formations 

 between the Pampean and the Santa Cruz, they are for the 

 most part so fragmentary as to be of no service in deciphering 

 the history of the group. In the Santa Cruz beds also they 

 are very abundant and varied, and several of the genera are 



