HISTORY OF THE EDENTATA 623 



but not in such preservation as to be of any service in this con- 

 nection. We find, as might be expected, many and very great 

 differences between the Pampean and the Santa Cruz repre- 

 sentatives of the suborder, the latter being in all repects less 

 modified and less widely removed from the armadillos. 



(1) The most obvious and striking distinction was in size, the 

 Santa Cruz forms being all small and some of them very small. 



(2) In all cases the carapace was made up of transverse 

 bands, which permitted a slight degree of flexibility, and near the 

 anterior end, at the margins of the shell, were two or three 

 overlapping bands. The plates were thin and were but rarely 

 coossified ; the ornamentation was made by shallow grooves. 



(3) The tail-sheath, which was of very uniform character, 

 consisted of two quite distinct portions ; the anterior region 

 consisted of 5 or more freely movable, overlapping rings, each 

 of two rows of plates, and in the posterior region the rings were 

 closely fitted together, less distinctly marked and not movable. 

 This posterior portion was sometimes thick and ended abruptly, 

 sometimes slender and tapering and in one genus (fAstero- 

 stemma) it was very armadillo-like. In none of the genera were 

 there any spines or horns, nor were the separate plates ever fused 

 together to form a tube. 



(4) There was considerable variety in the head-shield, which 

 was usually made up of many separate plates, but in one genus 

 (■\Eucinepeltus) they were coossified into a single heavy 

 casque. 



(5) The teeth had a less extreme height and the four an- 

 terior ones of each jaw were much simpler than in the Pampean 

 forms. An interesting survival was the retention of two mi- 

 nute incisors in each premaxillary bone, in one genus {fPro- 

 palceohoplophorus), but these were of no functional value and 

 were early lost. 



(6) The skull was much longer, narrower and lower and had 

 a relatively longer facial portion ; the occiput was higher and 

 more erect, and the condyles had no such elevation above the 



