LOXOLOPHODON AND UINTATHERIUM. 



35 



one pseudo-sacral. The centra rapidly diminish in size from before backwards. 

 The first is shorter than the last lumbar, but much longer than the other sacrals, 

 which are sub-equal. The pre-zygapophyses of the first resemble those of the 

 lumbar region — the metapophysis of the first being large, while it is tuberous 

 and rudimentary in the other three. The transverse processes are long and 

 wide in the first three ; widest in the first, but thickest in the second ; long and 

 thin in the fourth. The perforations for exit of the sacral nerves are wide and 

 deep. The pleuropophysial segments of the true sacrals are very heavy. The infe- 

 rior faces of the centra are slightly concave in the first three, and the first and 

 fourth are marked by slight hypophysial keels. The neural canal decreases to a 

 narrow opening in the last. 



Caudal Region. We possess the first four caudal vertebrae. The centra of the 

 caudal vertebrae are rather long, narrow, and greatly depressed in the middle ; 

 their slow decrease in size, the persistence of the backward-directed neural spines, 

 enclosing a narrow neural arch, point to a somewhat stouter tail than that of the 

 elephant. The transverse processes are wide, thin plates roughened at the ends 

 and projecting directly out ; they decrease in size backwards. 



Measurements of the VERTEBRiE, 



Uinta. 

 M. 



Dorsal Region. 



In anterior region: Diameter of centrum, fore-and-aft 075 



do. do., vertical 062 



do. do., transverse 142 



In posterior region: Diameter of last dorsal, vertical 087 



do. do., transverse no 



Neural canal, average width throughout the series 097 



Lumbar Region. 



Centrum, fore-and-aft diameter 095 



do., transverse diameter of posterior face in 



do., vertical diameter of posterior face 078 



Extreme width between transverse processes 214 



Width between prezygapophyses no 



Heighth of neural spine from lamina. 060 



Sacral Region. 



Length of sacral series (about \\\ inches) 264 



Transverse extent of sacral series 298 



First vertebra, diameter of anterior face (transverse) log 



do., vertical diameter of anterior face 072 



do., fore-and-aft diameter of anterior face 070 



Last vertebra, transverse diameter of posterior face 053 



do., vertical diameter of posterior face 031 



do., vertical diameter of neural canal 018 



