40 



Annals of the Carnegie Museum. 



relief and rest on the original block of sandstone on which they were 

 found. The neural spine of the first dorsal is broken off about ten 

 centimeteis above the neural arch, but judging from the size of the 

 fracture, the spinous process attained a length equal, and perhaps 

 even proportionally greater, than was the case in T. validum, w'th 

 which the Uinta remains have been compared. The second, third, 

 fourth, and fifth dorsals have their spines very nearly complete. In 

 proportion they agree quite well with those of the Oligocene genus, 

 but are more strongly inclined backward. As in Titanotherium the 

 transverse processes are not extremely heavy and the capitular facets 

 for the libs are of large size, while the sides of the centra are deeply 

 concave. The latter are deeper than broad and the inferior borders, 

 especially the posterior ones, are distinctly more keeled than in 

 Titanotherium. 



Back of the eighth dorsal there is a break in the vertebral column 

 and a number of bones are lost. A second block, which was found, 

 together with the one just described, contains portions of six posterior 

 dorsals and three lumbar vertebrae (see Fig. 6). The neural spines of 





(' 



Fig. 6. Diploceras osborni Peterson, 

 terior dorsals and the lumbar vertebrae. 



(Paratype. No. 2860.) X 9. Pos- 



the dorsal series are prominent and quite lumbar-like in their general 

 character. The zygapophyses are also of the interlocking lumbar type 

 and there are prominent metapophyses. The centra are somewhat 

 mutilated, but enough is preserved to indicate that they are deep and 

 ol comparatively small transverse diameter. 



There are, as stated, three lumbar vertebrae present in the paratype. 

 No. 2860. These bones are fortunately found in position succeeding 

 the last dorsal vertebra, and for the first time apparently furnish data 

 as to the correct number of the lumbar vertebrae of the Titanotheiiidae. 



