42 



NEW REPTILES AND STEGOCEPHALIANS FROM 



There are six caudals preserved, all chevron-bearing (fig. 13). It is probable 

 that there were two or three pygal vertebrae present. In the caudals preserved the trans- 

 verse process springs from the side of the neural arch and curves outward and down- 

 ward, becoming thin and more horizontal toward the distal end. The zygapophyses 

 are well developed, with the faces nearly flat; the characteristic recess continues at 

 the base of the neural spine, but with the decrease in height of the neural arches the 

 median descending vertical plate between the zygapophyses disappears, ihe first 

 three, which are evidently anterior caudals, have heavy spines with thickened apices. 

 The lower face of the centrum is marked by a median depression which separates two 

 strong ridges on the sides; these terminate posteriorly in the faces for the chevrons, 

 which look more downward than backward. 



Fig. 14. — Desmdtosuchus spurensis. All figures X 0.3. 



A. Upper surface of the seventh (?) rib of the left side. 



B. Lower view of A. 



C. Lower view of tenth rib, left side. 



D. Upper view of B. 



E. Upper view of eleventh rib, right side. 



F. Lower view of E. 



The last two caudals (fig. 13 c and d) are in poor condition, due to decay, but are 

 more elongated than the anterior ones, and there is a decided tendency for the posterior 

 faces to descend lower: than the anterior ones. 



The chevron bones (fig. 13 A and e) are widely separated at the proximal end, but 

 meet in a strong terminal portion. The exact length is not shown in any one. 



The ribs. — There were free ribs on all of the vertebrae of the presacral series, but 

 the posterior ones show a strong tendency to a close anchylosis with the transverse 

 process. Those of the cervical series were small and turned back close to the side of 

 the vertebrae, as is evidenced by the small amount of space between the vertebrae and 

 the sides of the dorsal armor. The first rib preserved was, in all probability, attached 

 to the seventh vertebra, as it was found close to it and fits the articulations quite closely. 

 This rib (fig. 14 A and b) is still short, and the capitular and articular processes are 

 nearly equal in length. The dorsal surface of the rib is expanded into a broad, thin 

 surface, which is supported by a thin, high ridge running the length of the rib on the 

 under side; this ridge has its origin on the tubercular process. 



