EDENTATA OF THE SANTA CRUZ BEDS. 99 



other Santa Cruz armadillo has unguals at all like these. In the hallux 

 the ungual is extremely small; in digit III it is symmetrical, and broader, 

 more depressed and more obtuse than in the others; in digits III and 

 IV it is asymmetrical, thicker and more pointed and in digit V it is small, 

 but larger than that of I. 



Systematic Position. Although the skeleton of Peltephilus is not so 

 completely known as that of several other Santa Cruz genera, the mate- 

 rial is sufficient to justify a decision upon its relationships and taxonomic 

 position. Ameghino has been so much impressed by the peculiarities of 

 the genus, that he has erected for it a separate order of the Edentata 

 ('94<7, 175). On the other hand, Moreno and Mercerat refer it to the Dasy- 

 poda and even to the Dasypodidce ('91, 57). 



That Peltephilus should stand as the representative of a distinct family, 

 seems abundantly clear, its peculiarities of carapace, dentition and skele- 

 ton being so many and so striking, and its isolated position, with refer- 

 ence to all the other contemporary genera, being so marked. At the same 

 time, as the foregoing description will show, Peltephilus is a genuine 

 armadillo, but with many divergent specializations, which lead away from 

 the other members of the suborder. In spite of the retention of a few 

 primitive features, it may be regarded as one of the most highly differ- 

 entiated of all known armadillos. However, none of these peculiarities 

 is radical, or fundamental ; the armadillo type is apparent in every part of 

 the structure and it seems altogether unnecessary, as well as misleading, 

 to remove the genus from the Dasypoda. Like Stegotherium, Peltephilus 

 formed the terminal member of its series, for no representative of this line 

 has been found in any formation later than the Santa Cruz. 



PELTEPHILUS STREPENS Ameghino. 



(Plate XVI, figs. 7-14.) 



Peltephihis strepens Amegh. ; Enumeracion sistematica, etc., 1887, P- 2 5- 

 Cochlops muricatns Amegh., in part; Contrib. al Conoc. de los Mamif. 



Eos. de la Rep. Arg., 1889, p. 792. 

 Peltepliilus heusseri Moreno and Mercerat; Revist. del Mus..de La Plata, 



T. II, 1891, p. 61. 



This is one of the larger species of the genus, being exceeded only by 

 P. grandis ; it is further characterized by certain features of the posterior 

 median plate of the cephalic shield, which is relatively long and narrow 



