42 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



the latter is the exceedingly low crown, the exposed portion being lower 

 than in any other Santa Cruz armadillo. 



The description of the skeleton can most conveniently be given in con- 

 nection with the various species. 



Relationsliips. Procntatns is evidently closely allied to the Pampean 

 genus Eittatns, though there is some difficulty in regarding any known 

 species of the former as ancestral to the latter. The Pampean genus is 

 much larger in size; its carapace consists of more numerous transverse 

 bands, 33 instead of 24 or 25 ; the pelvic buckler is relatively larger and 

 is made up of 12 or 13 bands, while in the Santa Cruz genus the number 

 can hardly exceed 10 ; the skull is quite different in appearance, having 

 more resemblance to that of Tatit, and the phalanges are reduced by co- 

 ossification to two in each digit. Among existing armadillos Proeutatns 

 most resembles the Dasypodidce in the restricted sense of that term. 

 Though the feet show no tendency to the peculiar type seen in Cabassous 

 and Priodontes, the trunk and limbs have many resemblances to those 

 genera. 



PROEUTATUS ROBUSTUS sp. nov. 



(Plates VIII-XI, XIII, Figs. 4, 5 ; XIV, Figs. 1-4.) 



This species is selected as the standard of comparison, because more 

 complete skeletons of single individuals are known from it than from any 

 other species of the genus. The type-specimen, collected by Mr. Hatcher 

 at Cornken Aike (No. 15,214), consists of a skeleton lacking much of the 

 carapace, the anterior end of the rostrum, the pelvis, tail and hind-limbs. 

 A second individual (No. 15,957) which retains most of the carapace, 

 many vertebrae, the pelvis, fore- and hind-limbs, was found by Mr. Peter- 

 son at the same locality. Other individuals, much less complete, are 

 probably referable to the same species. 



The species is characterized by its larger size and notably heavier pro- 

 portions than in those previously described, and by a somewhat different 

 pattern of sculpture in the carapace. Almost every part of the skeleton 

 shows characteristic features, to which attention will be called in the fol- 

 lowing description. 



Exoskeleton.- -The head-shield (Plates IX ; XIII, fig. 4) is made up of 

 irregularly polygonal plates, with rounded angles ; larger and smaller plates 

 are arranged with very little indication of a definite plan, except that in 



