On tlie Pareiasauriau f/eiius Propappus. 353 



and the height ahove the circular root ahout 15 mm. The cusps are 

 sharp and directed upwards. Five are situated on the top and 3 on 

 each side. 



The mandible has the greater part of both dentaries preserved, the 

 whole of the right splenial, and most of the right angular. The 

 dentaries have been broken through at the symphysis, but it is 

 believed that little is missing. There are 12 teeth-roots preserved in 

 the right dentary, and there may have been 2 others in a missing 

 fragment from the posterior part of the bone, but if nothing is 

 missing from the front of the bone it is unlikely that there were 

 more than 14 teeth in each jaw. The 12 teeth measure in a direct 

 line 132 mm. A number of badly preserved crowns of immature 

 teeth are seen, and in character they resemble those of the maxilla, 

 but the cusps are smaller. The dentary bone forms the greater part 

 of the outer side of the front part of the jaw. Its maximum depth 

 is about 65 mm., and its greatest length probably 170 mm. The 

 whole of the low^er border of the front part of the jaw and much of 

 the inner side is formed by the splenial, which on the inside of the 

 jaw measures 130 mm. The large angular bone fits in between the 

 posterior part of the dentary and the splenial. In Pareiasaurus it 

 has a single large rounded horn-like process, which passes down- 

 wards. In Propappus there are two horns. The posterior one, 

 which is by far the larger, measures 33 mm. in diameter at its base, 

 and it is 40 mm. in length. Its surface is not covered over by dense 

 bone like the rest of the jaw, and from its rough surface and cancel- 

 lous tissue one may infer that it was covered by horn. In front of 

 it is the second small horn core, whose basal diameter is 23 mm. by 

 18 mm., and whose height is only 15 mm. On the inside of the 

 angular is a fragment of the surangular, but there is no coronoid 

 bone preserved. Possibly it did not occur. The greatest thick- 

 ness of the jaw is near the posterior end of the dentary, where 

 it measures 45 mm. 



Vertehk^. 



The vertebrae are typically Pareiasaurian, though they present 

 some points of difference from those of Pareiasaurus. The 7 fairly 

 well preserved vertebrae are probably the 7 last dorsal. If we assume 

 that Propappus had 20 presacral vertebrae \\ke Pareiasaurus serridens, 

 then the 7 vertebrae would be the 14th to the 20th, which they may 

 be provisionally called. Each of the 7 resembles the others so 

 closely that it seems unnecessary to describe each separately. 

 Their chief characteristics are a rather slender elongated body. 



