NO. 8 UPPER EOCENE ARTIODACTYLA — GAZIN 69 



For example, P in Eotylopiis has become the caniniform tooth as in 

 Poebrotherium, whereas in Protylopus P has not yet surpassed the 

 canine in importance. 



Matthew, with specific reference to Eotylopus, was inclined to 

 stress lateral relationships in these primitive groups, but grouping 

 Eotylopus and its allies with the leptrotragulids with their more ad- 

 vanced selenodont dentition seems less clearly indicated. One could 

 perhaps make a better case for a not too remote relationship between 

 the poebrotherines and the leptotragulids, or between the oromerycids 

 and the agriochoerids. 



Genus OROMERYX Marsh, 1894 



Type. — Or ornery X plicatus Marsh, 1894. 



Discussion. — Oromeryx was the third of the Uintan artiodactyls 

 that Marsh named in 1877 but which remained nomina nuda until 

 their description and type designation in 1894. Marsh regarded Oro- 

 meryx as a cervid, but in subsequent references it has been considered 

 as a hypertragulid. Peterson (1919) included Oromeryx with Lep- 

 toreodon and Leptotragulus in the Hypertragulidae, but noted certain 

 resemblances to Protylopus. Direct comparison of the type materials 

 of Oromeryx and Protylopus reveals that there is very little of signifi- 

 cance distinguishing them. 



Marsh's illustration (1894, fig. 23) of the type specimen of Oro- 

 meryx plicatus is, as Peterson noted, a composite of the two sides, 

 and there are a number of inaccuracies in the drawing. The position 

 of P^ is shown as two alveoli. This tooth is actually broken of? level 

 with the palate, and the root portion is a single three-lobed structure, 

 which clearly divided into at least a fore-and-aft root within the 

 maxilla. The third lobe in a position supporting the deuterocone por- 

 tion of the tooth may well have had a separate root, but if not the 

 posterior root was evidently very broad and bilobed. P* is shown as a 

 simple bicuspid tooth whereas, in fact, the crest of the deuterocone 

 posteriorly divides the basin of the talon, leaving a deep and prominent 

 pocket posteriorly closed by the raised cingulum, quite as in the 

 Protylopus petersoni type specimen. Moreover, there are strong 

 plications on the posterior portion of the external surface of this 

 tooth (probably also on the anterior extremity of this surface as 

 well), variously developed in Protylopus petersoni. The external 

 styles and ribs of the upper molars are much more strongly de- 

 veloped, as Peterson noted, than the illustration shows, and the pos- 

 terior portion of the protocone is strongly bifurcate, extending a crest 



