72 PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



of Zaedyus, but resemble them in shape, except for the slight upturning 

 at the end seen in the recent genus, being somewhat convex in both 

 directions ; anteriorly, the nasals project a little beyond the premaxillaries 

 and have rounded tips. 



The premaxillaries are very long, forming most of the anterior end of 

 the rostrum, and are entirely edentulous ; the incisive foramen is very small 

 and apparently not divided by a spine ; the palatine processes are nar- 

 row, and are not clearly demarcated from the other part of the bone. 

 The anterior nares are small, terminal and much less oblique than in 

 Dasypus. The maxillaries, which are long and low, have their highest 

 point just in front of the orbits, though they are much lower here than in 

 Zaedyus, thence descending gradually forward and ending abruptly at the 

 straight, transverse premaxillary suture ; the alveolar process receives a 

 somewhat fluted appearance from the tooth-sockets ; the zygomatic pro- 

 cess is very prominent and is perforated by the small, circular infraorbital 

 foramen ; the palatine processes are long, narrow and slightly concave in 

 both directions, widening a little posteriorly between the slightly divergent 

 rows of teeth. The palatines form a considerable part of the hard palate, 

 extending it for some distance behind the last tooth. As a whole, the 

 hard palate most resembles that of Zaedyus, but is considerably narrower. 

 The pterygoids are very small and apparently have no hamular processes. 

 In shape and position the posterior nares resemble those of Zaedyus, but 

 are relatively smaller ; they are short, low and narrow, with nearly straight 

 front border and are placed well back of the teeth. 



Among existing armadillos, the mandible of Zaedyus is most like that 

 of the fossil, but with many small differences ; in the fossil the horizontal 

 ramus is long, slender and shallow, tapering anteriorly to a blunt point, 

 and the symphysis is very short ; the ascending ramus is high and narrow, 

 with the condyle raised much above the level of the teeth ; the angular 

 process is a long hook, terminating in an upturned point and is much better 

 developed than in the modern genera ; the ventral border of the ascending 

 ramus is sinuous, concave in front and convex behind and very different 

 from the regular, convex curvature of Zaedyus ; the masseteric fossa is high 

 and narrow, but deeper than in recent armadillos. The coronoid is 

 slender and erect, shorter, narrower and much less recurved than in 

 Zaedyus; the sigmoid notch is broader and the condyle is smaller, but of 

 similar transverse and concave shape. 



