EDENTATA OF THE SANTA CRUZ BEDS. 69 



of oval cross-section, non-lobate, so far as can be judged from z and *, the 

 only teeth in position, and from the alveoli of the others. 



In size, this species is considerably smaller than any of those referred 

 to the preceding genus. 



PROZAEDIUS Ameghino. 



(Plates V, VI, Figs. 1-18.) 



Eiiphractiis Amegh. (non Gervais) in part; Enumeracion sistematica, etc., 



1887, p. 26. 

 Zaedyus Amegh. in part ; Contrib. al Conoc. d. Mam. Fos. de la Repub. 



Argent, 1889, p. 867. 



Prozaedius Amegh. ; Revista Argentina de Hist. Nat., T. I, 1891, p. 327. 

 Dasyptis Lydekker, in part ; Anales del Museo de La Plata, T. Ill, 1894, 



P- 55- 

 A genus of small armadillos very closely allied to the recent Zaedyus, 



which was doubtless derived from some member of it. 



Exoskeleton (Plates V, VI, figs. 2, 13, 14). As usual in the Santa Cruz 

 genera, the carapace has no anterior buckler, but is made up of at least 

 fourteen, and probably more, movable bands ; the pelvic buckler is rela- 

 tively small and is composed of eight bands, including the marginals. 

 The sculpture, which differs slightly in the various species, is essentially 

 like that of the recent Zaedyiis ciliatus. In the movable bands, the plates 

 of which are long and narrow, the pattern consists of three longitudinal 

 ridges, of which the median one is the narrowest and most sharply de- 

 fined, while the laterals show a more or less pronounced tendency to break 

 up into rows of tubercles ; the marginal scutes are smooth and marked 

 only by a fine pitting. In the pelvic buckler the plates become shorter 

 and relatively wider posteriorly, but they are throughout narrower and 

 more elongate than in the recent species ; the sculpture is that of the mov- 

 able plates, modified by the conversion of the lateral ridges into rows of 

 tubercles, which extend across the anterior border of the plate and thus 

 reduce the length of the median ridge, which remains entire. The hinder- 

 most row of scutes forms a series of bluntly-pointed marginals, which retain 

 the sculptural pattern much more distinctly than in the recent species. 



The cephalic shield is composed of numerous small, irregularly polygonal 

 plates, which do not overlap at all, but are in contact only by their edges ; 

 their markings are only very numerous minute pits. 



