III. A SMALL TITANOTHERE FROM THE LOWER UINTA 



BEDS. 



By 0. A, Peterson. 



Heterotitanops parvus gen. and sp. nov. 



Plate XI. 



Type. — Skull, lower jaws, vertebral column, ribs, limb-bones, 

 calcaneum, and astragalus of young individual. No. 2909. 



Horizon. — Upper A., Uinta Eocene. 



Locality. — White River, Uinta County, Utah. 



The specimen on which this genus is proposed is unfortunately a 

 very young individual, the only material representing this form in the 

 entire collection. It was found articulated in hard sandstone con- 

 cretion, and lower down in horizon A of the Uinta sediment than any 

 mammalian remains heretofore described from that formation. 



Generic Characters. — Dentition: If? Cy? Pf? Mf. Deciduous den- 

 tition: If? Cy Mf?. Rapid increase in size of the deciduous upper 

 cheek teeth from first to last tooth. D- ivith perfectly formed internal 

 tubercles (proto- and hypocones) and the antero-external angle very greatly 

 developed. Molars hypsodont. if- icith large conical proto- and hypo- 

 cones, the external faces of the ectoloph less emarginated antero-posteriorly 

 than in the Titanotheres generally and the median vertical ridge of the 

 ectoloph projecting forward to a greater degree. 



General Description. — The skull and lower jaws were found in the 

 talus and separated from the rest of the skeleton. The front of the 

 nasals, the premaxillaries, and symphysis of the lower jaws were 

 broken off and were not recovered. The vertebral column and the 

 ribs were, as stated, found in position, but all of the feet, except the 

 left calcaneum and astragalus, are lacking. The skeleton pertains to 

 a very young individual, so that the characters here presented may not 

 in all cases compare well with those in fully adult specimens. 



The facial region is rather short, the large orbit being placed well 

 forward. The latter is bounded posteriorly by a postorbital process 

 of the frontal which is considerably developed. The infraorbital 

 foramen is of large size and placed well above the alveolar border. 



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