EDENTATA OF THE SANTA CRUZ BEDS. 7 



pes is pentadactyl and, except in the glyptodonts, is plantigrade, while in 

 the latter group it is semidigi'tigrade. No coossification occurs in tarsus, 

 metatarsus or phalanges, and the unguals, which in the ground-sloths are 

 large claws, in the other two orders are more or less hoof-like, completely 

 so in the glyptodonts. 



DASYPODA. 



The Santa Cruz armadillos form a peculiar assemblage of types, very 

 unlike, as a whole, the modern representatives of the suborder, for only 

 one, or possibly two, species would appear to be directly ancestral to ex- 

 isting forms, while the majority belong to extinct lines. Some of these 

 lines, like that of Proeutatus, for example, persisted till a much later per- 

 iod than the Santa Cruz, and reached their culmination in the Pampean, 

 but have no representatives in the recent fauna, while other series, like 



FIG. i. 



Skulls of Santa Cruz armadillos, x f . a, Stegotlurium tcsselatum ; b, Prozaedius exilis ; c, 

 Stenotatus patagonicus ; d, Procntatus lagcita. 



Stegotlierium and the extraordinary PeltepJiilus, are not known to pass be- 

 yond the limits of the Santa Cruz formation. At the same time, there is 

 a very notable diversity among these armadillos and no less than* three 

 families and seven genera have been described, most of the genera hav- 



