Peterson: A New Titanothere from the Uinta Eocene. 39 



Oligocene; the articulating surface for the atlas is located more 

 laterally, and the postzygapophysis has a greater vertical obliquity 

 and a more nearly rounded outline than in the latter. In the Princeton 

 specimen^- it is seen that the attcrial canal is located back of the pos- 

 terior edge of the articulation for the atlas, while in Diploceras oshorni 

 the foramen is, on a direct side view, partially hidden by the back- 

 wardly extended process of the articulation. I judge that the axis, 

 as a whole, in the present form is relatively shorter than in'the Prince- 

 ton specimen. In more minute details the description of Scott and 

 Osborn (/. c, p. 514) agrees well with the parts pieserved, in the speci- 

 men before me, i. e., the heavy spine overhanging the postzygapo- 

 physes, the inner turn of the transverse process, and a prominent in- 

 ferior keel. 



The succeeding four cervical vertebrae in the paratype, No. 2860, 

 are represented only by fragments. They appear to have short 

 opisthocoelian centra, as in Diplacodon, described by Marsh and 

 Osborn, and a prominent ventral keel. 



Fig. 5. Diploceras oshorni Peterson 

 cervical and dorsal vertebrae. 



(Paratype. No. 2860.) 



Last 



The seventh cervical vertebra is completely worked out in half relief 

 and shows the chief characteristic features. Fig. 5. The long and 

 pointed spinous process is well shown, as is also the neural arch and 

 the centrum. The pre- and post-zygapophyses are, as in the axis, 

 located quite laterally and face directly upward and downward as in 

 Titanotheriiim. The transverse process shows a tendency to develop 

 the broad round termination found in T. validiim of the Oligocene. 



Theie are eight doisal vertebrae which are worked out in half 



12 Scott, W. B., and Osborn, H. F., "The Mammalia of the Uinta Formation," 

 Trans. Amer. Philos. Soc, Vol. XVI, Part III, 1889, p. 514, PI. IX, Fig. 15. 



