242 PATAGONIAN EXPEDITIONS! PAL/EONTOLOGY. 



versely oval. In both individuals 7 resembles -%, while T is transversely 

 extended and not subcylindrical. 



The mandible itself displays no important peculiarities ; the predental 

 beak most resembles that of H. rostratus, being short, broad at the base 

 and tapering rapidly forward, with strongly everted or flared dorsal 

 borders. 



MEASUREMENTS. 



Type. La Plata Specimen. 



Lower dentition, length 034 -O 2 95 



" " " v-ii 02 3 - Ol8 5 



T , length (/. e., antero-posterior diameter) 0055 .005 



" width (i. e., transverse diameter) 0045 -0035 



y , length 007 .005 



" width 009 .008 



j, length 007 .005 



" width 0085 .009 



f, length 007 .006 



" width 0085 .008 



HAPALOPS CONGERMANUS Ameghino. 



Amphihapalops congermanus Amegh. ; Rev. Argent, de Hist. Nat., T. I, 



1891, p. 319. 



Amphihapalops gallaicus Amegh. ; Ibid., p. 319. 

 Amphihapalops cadens Amegh. ; Ibid., p. 320. 



This very imperfectly known species is of doubtful validity ; it is of 

 medium size and is distinguished by the elevated position of the postero- 

 external opening of the dental canal, which is placed higher upon the 

 ascending ramus than in any of the preceding forms. The three species 

 which Ameghino has named do not differ from one another more than 

 would be expected from the very different ages of the type-specimens. 



Ameghino has proposed a genus, Pseudliapalops, which is characterized 

 by the position of the postero-external opening of the dental canal ; this 

 foramen opens laterally, instead of anteriorly, and is situated upon the 

 horizontal rather than the ascending ramus. Although this is a fairly con- 

 stant character, with comparatively few intergradations, it does not seem to 

 be of sufficient importance to require a generic distinction. The astraga- 

 lus found with the type-specimen of P. observation is was evidently in only 



