200 THE merycoidodontim: 



Genus POATREPHES Douglass 1903 



Table 1 



Original Reference: New vertebrates from the Montana Tertiary. Ann. Carnegie Mus., II, p. 176. 



Genotype : Poatrephes faludicola Douglass. 



Genoholotype: Cat. No. 845 CM., skull, rather mutilated and distorted. 



Distinguishing Characters: See under the Specific Characters of the only species. 



Discussion: With the scanty material at hand it is very difficult to be sure of the affinities of 

 this genus, especially as the teeth are badly damaged and their characters obscured. I consider it to 

 be a derivative from the Ticholeftus stock but an aberrant branch. 



It is of upper Miocene age and very close to Ticholeftus, especially to T. zy gomaticus , but is 

 not that species, since the molar and premolar series are nearly equal in length, in fact the latter is 

 slightly longer than the former. 



Etymology: Poatrephes (grass + to feed). 



Poatrephes paludicola Douglass 1903 



Fig. 145 ; PI. XXVII, figs. 1-2 



Original Reference: New vertebrates from the Montana Tertiary. Ann. Carnegie Mus., II, pp. 176- 

 178, fig. 17. 



Type Locality: Near New Chicago, Montana. 



Geologic Horizon: Upper Miocene (Flint Creek). 



Type: Genoholotype, Cat. No. 845 CM., skull, somewhat mutilated and distorted. 



Specific Characters: The skull is elongate and slightly longer than that of Eporeodon. 

 The zygomatic arches are heavy forward and lighter aft, apparently having their greatest expan- 

 sion below the posterior part of the orbits, a rather unusual character in the merycoidodonts. The 

 anterior part (malar) of the arch is broad and heavy and spreads widely under the orbits, with the 

 outer part curving downward and the border roughened and very concave anteroposteriorly. The 

 anterior lower root is but slightly above the alveolar margin. The anterior branch of the squamosal 

 is long and slender, terminating below the posterior quarter of the orbit. This process invades the 

 malar for some distance, and posteriorly it rises gradually, with a convex inferior margin. The 

 anterior borders of the premaxillaries are thick and do not rise so abruptly as in Mesoreodon or 

 Eporeodon. These bones are not coossified. Apparently there were facial vacuities, according to 

 Douglass, but he was not certain of this, because of the imperfection of the type skull, for he wrote: 

 "On one side there is a large circular space anterior to the orbits which has no bone and the surround- 

 ing bone, in part, appears to be unbroken." Of this character we cannot be sure until more perfect 

 material is found. The nasals are entirely missing. The lacrimal bone appears to be small on the 

 face, without a marked fossa. The frontals are large and rather flat medially, curving gently down- 

 ward above the orbits. They seem to extend as far forward as do the lacrimals. The orbits are 

 closed by a heavy postorbital bar and are moderately small, looking mainly outward but slightly 

 upward. They are situated about in the middle of the height of the skull. The temporal ridges are 

 not raised, extending nearly in a straight line from the postorbital bar to a median point in a plane 

 above the middle of the glenoid articular surface, and there uniting to form a moderately long, high 

 sagittal crest. The supraoccipital crest appears to have but a slight overhang, and the wings are 

 widespread. 



