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UINTA SELENODONTS 



space for three full-sized teeth ; however, the point is not an easy one to 

 decide. The canine is of the typical oreodont (or agriochoerid) pattern, as is 

 plainly apparent, although both canines are broken away nearly level with the 

 alveolus. From the broken surface several facts may be learned : the section 

 is D-shaped, with the posterior surface nearly plane or even slightly concave, 

 while the fang is curved, much as in Agriochosrus . From the characteristic 

 form of this upper canine we may confidently infer that, as in Proiorcodon, the 

 lower canine had already gone over to the incisors and that py had assumed 

 its shape and function. 



The first premolar also is represented only by the roots, the crown being 

 broken on each side. This tooth follows the canine after an interval which is 

 relatively no greater than in Protorcodon, and this lack of a diastema con- 

 stitutes a very marked difference from Agriochoertis. Another difference from 

 the latter is in the proportionately larger size of p--, for though it was evidently 

 the smallest of the series, it was not so much reduced as in the White River 

 genus. The second premolar is larger in every dimension than pi, especially 

 in the antero-posterior one ; the crown is shaped much as in Protorcodon and 

 has the same cordate outline, with acutely pointed and slightly recurved apex; 

 it differs, however, in the much better development of the internal cingulum, 

 which on the posterior half of the crown encloses a shallow fossette. In 

 Agriochccrtis p-2- is very much as in the Uinta genus, except that it is less com- 

 pressed and considerably thicker transversely. 



Seen from the outer side p- closely resembles p-, but when looked at 

 from below or within it is markedly different, for it has a well developed deu- 

 terocone and is carried upon three fangs. The deuterocone is larger than in 

 Protorcodon, and is even more distinct than in Ag?iochcerus , and, as in the latter, 

 this internal cusp has an asynmietrical position near to the posterior border of 

 the crown. The fourth premolar is a little shorter antero-posteriorly than p-2- 

 or p-*-, but is broader than either ; the deuterocone is now a symmetrically 

 developed crescent, the apex of which is placed opposite to that of the proto- 

 cone. In Agriochivrus this tooth is almost molariform, having two external 

 and in some species two internal cusps, though the postero-internal one 

 (tetartocone) is always small and sometimes absent. From the simplicity of 

 pA in the Uinta genus it may be inferred that the corresponding lower tooth 

 was not molariform, as it is completely in the White River genus. 



While the premolars of Protagriochcerus are not especially suggestive of 

 relationship with Agriochcerus rather than with Oreodon, the molars are pre- 



