OREODON. rs 
and occupied a position with them in the functional series, but remains after these 
are shed. 
In comparing Prof. Owen’s figure of the series of upper molar teeth of Hyopo- 
tamus ‘vectianus (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 difference in the 
relative extent of their abrasion. In.the lower jaw of an undoubtedly adult indi- 
vidual of another species, Hyopotamus bovinus (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. 
@reodon Culbertsonii. 
(Pu. II.; IlI.; IV. Figs. 1-5; V. Figs. 1, 2; VI. Figs. 8-11.) 
Merycoidodon 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, y. 239. 
Oreodon Culbertsonii, Leidy: Owen’s Report of a Geol. Survey of Wisc., 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 IL. Fig. 1.) 
From the collection of Mr. T. A. Culbertson. 
MEASUREMENTS." 
Inches. Lines. 
Height of face from infra-orbitar foramen to the end of the angular process of 
the os frontis . : : 3 5 : : : F : ; ah al 4 
Distance of supra-orbitar foramina from the ossa nasi a 
Height of symphysis of lower jaw. : i : ; 5 : i Pal 8 
1 As far as the specimens permit, measurements are given to show the variations which may in this way 
exist in different individuals. 
7 
