PROTOREODON 



33 



Etymology: Protoreodon (first + Oreodon); Eotneryx (dawn + ruminant); Agriotherium 

 (wild + beast). 



Species: 



P. medius Peterson 1919. 



P. minor Scott 1 899. 



P. faradoxicus (Scott) 1898. 



P. parvus Scott and Osborn 1887. Genotype. 



P. fumilus (Marsh) 1875. 



P. species. 



Protoreodon medius Peterson 1919 

 Figs. 3, 8; PI. I, fig. 1 ; PI. XXXIX, fig. 1 



Original Reference: Report upon the material discovered in the Upper Eocene of the Uinta basin by 

 Earl Douglass in the years 1908-1909, and by O. A. Peterson in 1912. Ann. Carnegie Mus., XII, pp. 82-84, 

 fig. 13; pi. XL, figs. 1-16; pi. XLI. 



Type Locality: Six miles east of Myton, on the Duchesne River, Utah. 



Geologic Horizon: Upper Eocene (Uinta — Hor. C). 



Types: Holotype, Cat. No. 2962 CM., greater portion of a skeleton. Paratypes, Cat. No. 2917, pair 

 of mandibles; Cat. No. 2933, left inferior ramus; Cat. No. 3020, part of skeleton, with nearly complete tail; 

 and Cat. No. 3038, partial skeleton; Cat. Nos. 2987 and 3067, skulls of young individuals. All types in the 

 Carnegie Museum. 



Specific Characters: This is the largest species of the genus. Unfortunately the holotype 

 skull and jaws have not been separated from the matrix, and the superior and cranial regions of the 

 skull are mainly missing. Consequently the characters are drawn partly from the paratypes. 



Skull: The skull is about 12 per cent longer than that of P. fumilus, the next largest species. 

 The face, including the orbit, is half of the skull length. The zygomatic arch is of about uniform 

 depth, nearly parallel with the dentition and rising very slightly to the low crest, which in turn rises 

 about to the level of the postfrontal process of the malar, above the posterior of the glenoid articular 



Fig. 8. — Protoreodon medius Peterson. Skull and jaw. HT. Cat. No. 2962 CM. 1/2 nat. size. (After Peterson, 1919.) 



surface. The long nasals extend forward to a point nearly above the incisor border. There is no 

 lacrimal fossa. The frontal bones are narrow and nearly flat and have a gentle lateral decurvature. 

 The orbits are almost circular and of proportional size. The temporal ridges unite rapidly just 

 behind the postorbital constriction to form a high, thin sagittal crest, somewhat less than a third of 

 the skull length. The supraoccipital crest is well produced, and the wings are not far apart. The 

 basicranial axis is moderate in slope. The brain case is long and narrow, and the postglenoid 

 processes are large. 



