146 REPTILIA. 



sutures between the elements of the palate cannot be traced in the 

 known specimens ; but the general aspect of this region is indicated 

 in the accompanying diagram (fig. 93). The basioccipital (b. occ.} is 

 short, the basisphenoid (b. s.) longer ; and the latter bears the usual 

 stout lateral processes for articulation with the pterygoids. Immediately 

 in front of this articulation there is the usual interpterygoid vacuity 

 (i. pt.}. Each pterygoid sends outwards and backwards a robust branch 

 (p. pt.} to the quadrate (qu.), but loses its identity in the other bones 

 of the palate in front. These are remarkable for the numerous series of 

 small teeth which they bear, arranged as indicated by the minute circles 

 in the diagram. The two foremost longitudinal series of teeth (v) are 



FIG. 92. 



Pariasaurus baini ; side view of skeleton, about one-thirtieth nat. size. Karoo 

 Formation (Permian or Triassic) ; Cape Colony, South Africa. (After 

 Seeley.) 



doubtless fixed on the vomers, which separate the large posterior nares 

 (pt. na.}. The maxillse and premaxillae do not appear to possess a palatal 

 extension ; they are provided with a single uniform series of much larger 

 teeth than those of the palate, each with a slightly expanded and com- 

 pressed, serrated crown. These teeth are directed a little inwards, while 

 those of the comparatively small mandible are inclined slightly outwards 

 to meet them ; but no traces of wearing have been observed. The 

 mandible is not produced behind the articular facette, and the sutures 

 between the various elements cannot be traced ; but the two rami appa- 

 rently meet in open suture at the symphysis. A curious feature consists 

 in the presence of a slight boss below the symphysis, and a larger pair of 

 bosses behind, one on the inferior aspect of each ramus. The vertebral 

 centra are biconcave, and there are relatively small wedge-shaped inter- 

 centra (hypocentra) between all those of the dorsal region. The number of 

 presacral vertebrae is about 18 in P. baini, and each (except perhaps the 

 atlas) shows a deepened but undivided articulation for the single-headed 

 rib. The sacrum comprises four vertebrae, which are not fused together. 



