Vol. 4] Sinclair. — John Day Rodents and Ungulates. 



133 



three roots. The crown has two cusps, a protocone and a deutero- 

 cone and there is a strong external cingulum. The pattern of 

 of the anterior molars is entirely obscured by wear. Anterior 

 and posterior cingula are rather prominently developed. M 3 was 

 found separate in the matrix. In this tooth the broad dome- 

 shaped hypoeone is unworn, while the remaining cusps are 

 much reduced. There is a broad anterior cingulum. but no 

 posterior cingulum is observable. 



In the mandible, P 3 has been shed on either side and the 

 alveolus closed. P 2 , preserved only on the right ramus, resembles 

 the smaller premolars of the upper series. P.. has been shed, the 

 alveolns on the right side only remaining open. Anterior and 

 posterior cingula are well developed on the lower molars. In M 3 

 the hypoconulid is not differentiated from the posterior cingu- 

 lum, which projects slightly forming a very small heel. 



The right side of the cranium has been badly crushed. The 

 left side is less distorted. The chief point of specific value at- 

 taching to the cranium is in the shape and direction of the jugal 

 processes. These processes are plate-like with a thickened me- 

 dian rib. The free edges, especially the anterior, are thin and 

 sharp. The processes are short, not extending below the lower 

 mandibular border. The orbits are posterior in position, their 

 anterior borders lying above the posterior edge of M 3 . 



The mandible is peculiar in the absence of the knob-like 

 bosses on the chin, which are so prominently developed in E. 

 ingens and E. hn per at or* The protuberances beneath P 4 are 

 small and deeply cupped. The dependent angle slopes gradually 

 backward without the abrupt downward curvature characteriz- 

 ing E. ingens. 



With the skull were preserved the atlas, axis and three an- 

 terior cervicals, all considerably crushed, fragments of a radius, 

 an imperfectly preserved tibia, an astragalus, the right and left 

 unciform and navicular, the left pyramidal, the fused ecto-meso- 

 euneiform, a scaphoid, a third metatarsal and a phalanx. These 

 do not differ sufficiently from E. ingenus as described by Scott to 

 warrant separate description here. 



* W. B. Scott, The Osteology of Elotherium. Trans. Am. Phil. Soc, Vol. 

 XIX, p. 285. 



