68 



THE MERYCOIDODONTID/E 



Foramina: The infraorbitals lie above the interval between P 3 and P 4 . The supraorbitals are 

 15 mm. apart. The foramen rotundum is certainly present on the left side but is small, and it is 

 absent on the right side. The posterior palatines are located opposite the extreme anterior part 

 of M 1 . 



Dentition: The superior molar and premolar series are nearly equal in length, with an index 

 of 0.96. The canines are less robust than in E. pacificus. P 4 is proportionally reduced, and there 

 is a diastema on either side of P 1 . 



Discussion: This John Day skull is interesting in the presence of the foramen rotundum, 

 although it is only on one side and was probably not functional. The species was named in honor 

 of the Reverend Thomas Condon, to whom is due the distinction of first bringing to the attention of 

 scientists a knowledge of the great fossil deposits of the John Day Basin. 



Fig. 34. — Eforeodon dickinsonensis (Douglass). Skull and jaw. HT. 



Douglass, 1907.) 



Cat. No. 15 84 CM. 1/2 nat. size. (After 



Eporeodon dickinsonensis (Douglass) 1907 

 Figs. 4, 34; PL IV, figs. 1-3 



Original Reference: Some new merycoidodonts. Ann. Carnegie Mus., IV, pp. 99-100, pi. XXII 

 (Eucrotaphus dickinsonensis) . 



Type Locality: Near Dickinson, North Dakota. 



Geologic Horizon: Middle or upper Oligocene. 



Type: Holotype, Cat. No. 1584 CM., nearly complete skull and jaws, together with greater portion of 

 vertebral column and fragments of limb and foot bones. Collected by Earl Douglass in 1905 and named after 

 the town of Dickinson. 



Specific Characters: The skull is about the size of that of Merycoidodon culbertsonii and 

 is mesocephalic. The superior profile in lateral view is convex, with the highest point above the 

 orbits. The zygomatic arches have been restored, but the malar portion is somewhat lighter than 

 normal for the genus. The nasals are uniformly wide, except for the posterior attenuation which 

 ends in a point and the anterior part which is missing. The pars facialis of the lacrimal bone is 

 moderately large, and the antorbital pit is shallow and reduced. The frontals are wide and convex 



