THE UPPER TRIASSIC OF WESTERN TEXAS. 



41 



The posterior dorsal vertebrae (fig. 12 E and F) become heavier in all of their propor- 

 tions; the spines remain thin transversely, but the apex becomes heavier; the transverse 

 processes become shorter by the abbreviation of the distal end, so that the capitular 

 face approaches the tubercular. Even in the posterior dorsals the sides of the neural 

 arch remain elevated and the transverse processes take their origin entirely from them. 

 The edges of the faces of the centra are expanded so much that a section of the middle 

 of the centrum is not more than half as large as that of the faces. 



FIG. 13. Desmatosuchus spurensis. All figures X 0.3. 



A. Posterior view of the first true caudal vertebra. 



B. Lateral view, left side of A. 



C. Lateral view of a median caudal vertebra with the incomplete chevron, left side. 



D. Lower view of C. 



E. Posterior (upper) view of the chevron shown in C. 



The posterior presacral vertebrae resemble those of the dorsal series in all major 

 particulars; the last three or four become decidedly heavier, with larger centra, and the 

 transverse processes become broader antero-posteriorly, with the tubercular and capitu- 

 lar faces at nearly the same distance from the origin of the transverse process. The 

 ribs are lost, but there is evidence that even to the last the ribs were articulated with 

 the transverse process and not reduced and coossified with them ; in this sense there are 

 no true lumbars. 



A single very poorly preserved vertebra which seems to have a very heavy neural 

 spine and a short, heavy transverse process, or origin of a sacral rib, may be regarded as 

 one of the sacrals. This region is in poor condition; only a portion of a very poorly 

 preserved half of the pelvis, as noted below, is preserved. 



