270 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



what smaller proportionately. The upper molariform teeth are broad trans- 

 versely, much compressed antero-posteriorly and either oval or obscurely 

 trapezoidal ; in the mandible these teeth are more constantly oval. 



MEASUREMENTS. 



Type. E. latifrons. E. lafonei. 



Upper dentition, length 060 .054 .063 



" < A-.fi. .032 .031 .034 



1, length (*'. e., antero-posterior diameter) 008 .008 .0105 



" width (/. e., transverse diameter) 006 .005 .008 



4 ( length 0065 .0068 .0065 



" width oio .0095 .0095 



A, length 007 .007 .0065 



"width oil .oil .0105 



A, length 006 .007 .006 



" width on .010 .010 



*, length 005 .005 .005 



" width 009 .008 .008 



Type. No. 9,241. No. 9,575. No. 15,314.. 



Lower dentition, length 037 .041 .041 .043 



" " " s _ 4 024 .026 .026 026 



T , length 007 .007 



" width .006 



j, length 006 .007 .007 006 



" width .010 .010 .009 



y , length 0065 .0065 



" width .010 



T , length 008 .007 



" width .0095 



So far as can be judged from the available specimens, the skull resem- 

 bles that of R. externus, with elongate and rather narrow cranium, short 

 and very broad face ; the upper contour of the skull is straighter than in 

 most species of Hapalops, the parietal eminence rising but little above the 

 summit of the occiput. As appears to be always the case in this genus, 

 the occipital crest is much better defined than in Hapalops and the sagit- 

 tal crest, though low and thin, is very distinct and ends anteriorly in 

 rugose temporal ridges. The postorbital constriction is much shallower 

 than in Hapalops, but the preorbital fossae are made very deep by the 

 conspicuous prominence of the caniniform alveoli. 



The occiput is low and wide, is inclined slightly forward and is almost 

 plane, except for a broad median convexity, which bears near the dorsal 



