On the Pareiasaurian genus Propappus. 359 



development of dermal ossifications. PareiasaurHs is known to have 

 a few small bony plates round the spines of the vertebrae, but Pro- 

 pappus must have had the whole back and probably sides covered 

 with a carapace of bony plates somewhat after the manner of the 

 crocodile. They vary in size from plates 50 mm. in diameter to 

 little bony nodules about the size of peas. The larger ones have a 

 central boss and irregular radiating ridges. At the edges they over- 

 lap each other, and it seems probable that the carapace was not 

 quite rigid. It extended at least as far out on the sides as 300 mm. 

 from the middle line. There is no evidence of any plastron. 



