OREODON^ 45 



and occupied a position with them in the functional series, but remains after these 

 are shed. 



In comparing Prof. Owen's figure of tlae series of upper molar teeth of Eyopo 

 tamus vectianiis (in Plate VII. Vol. IV., of the London Quarterly Journal of the 

 Geological Society), with that stage of the dentition of Oreodon in which the per- 

 manent true molars occupy their functional position in company with the deciduous 

 teeth, I cannot avoid a suspicion that what are represented as the third and fourth 

 permanent premolars (the latter of which has the exact form of the succeeding 

 permanent true molars), are really deciduous teeth, which were to give place to 

 more simple, bilobed, anthracotheroid, permanent premolars. The teeth, however, 

 represented as of the latter character, to belong to the deciduous series, appear too 

 slightly worn in relation to the condition presented by the first permanent true 

 molar, although it is not improbable that the permanent true molars might follow 

 the eruption of the deciduous teeth so rapidly as to exhibit little difierence in the 

 relative extent of their abrasion. In the lower jaw of an undoubtedly adult indi- 

 vidual of another species, Hyopotamus hovinus (represented in Fig. 3 of Plate VIII. 

 of the same work), it is observable that the anterior two permanent true molars 

 are deeply worn, while the two permanent premolars in advance are but slightly 

 abraded, which could not be the case under such circumstances as those presented 

 by the upper teeth in the figure first referred to. 



Oreodon Culfiertsonii. 



(Pl. II. ; III. ; IV. Figs. 1-5 ; V. Figs. 1, 2 ; VI. Figs. 8-11.) 



Meryeoidodon Culbertsonii, Leidy: Proc. Acad. Nat. Sci., 1848, iv., 47, pl. figs. 1-5. 



Oreodon priscus, Leidy: Proc. Acad. Nat. Sci., 1851, v., 238. 



Cotylops speciosa, Leidy: Proc. Acad. Nat. Sci., 1851, v. 239. 



Oreodon Culbertsonii, Leidy : Owen's Report of a Geol. Survey of Wise, etc., 548. 



Of this species of Oreodon, I have had the opportunity of examining the fol- 

 lowing specimens : — 



1. A very much fractured skull, with the posterior extremity, zygomata, post- 

 orbital arches, upper margins of the orbits, upper part and left side of the end of 

 the nose, and most of the teeth of the left side broken away. 



On the right side, the entire series of teeth exist in both jaws in a state almost 

 as perfect as when the animal was living. (Plate II. Fig. 1.) 



From the collection of Mr. T. A. Culbertson. 



MEASUREMENTS.^ 



Inches. Lines. 

 Height of face from infra-orbitar foramen to the end of tlie angular process of 



the OS frontis 1 * 



Distance of supra-orbitar foramina from the ossa nasi . . . . • ' 



Height of symphysis of lower jaw .....■■• 1 ° 



^ As far as the specimens permit, measurements are given to show the variations which may in this way 

 exist in different individuals. 



7 



