2 20 THE OSTEOLOGY OF THE REPTILES 



Skull elongate and compressed in front. Cleithrum small, tail 

 elongate. 



Limnoscelis Williston, United States. 



Family Pantylidae (Pantylosauria) . Terrestrial reptile less than 

 two feet in length. Skull low, short, fiat, with palatal and coronoid 

 teeth; a single row of short teeth in [upper] jaws and mandible. 

 Skeleton imperfectly known. No parietal foramen. Body covered 

 with small bony scutes. 



Pantylus Cope (? Ostodolepis Williston), United States. 



2. Middle and Upper Permian 



Family Pariasauridae (Pariasauria) . Large lowland cotylosaurs 

 reaching nine or more feet in length. Skull with protuberances, 

 broad and short, its intimate structure not well known. Teeth in a 

 single row, convex on the outer side with six or seven cusps arranged 

 around their borders. Scapula with acromion and screw-shaped 

 glenoid fossa. Phalangeal formula of front feet unknown. Astrag- 

 alus and calcaneum fused ; centrale and fifth tarsale unknown, pos- 

 sibly absent. Phalangeal formula believed to be 2, 3, 3, 4, 3 in one 

 genus, primitive in others. Body with several rows of bony dermal 

 scutes. 



. Pariasaurus Owen, Propappus Seeley, Anthodon Owen, Brady- 

 saurusW2it's,on, Embrithosaurus Watson, Pariasuchus Haughton and 

 Broom, South Africa. Pariasaurus or an allied genus, Russia. 



3. Lower and Middle Triassic 



Family Procolophonidae (Procolophonia). Small reptiles a foot 

 or more in length. Skull triangular, relatively smooth. Teeth in front 

 conical, behind transverse, in a single row. Orbits very large, elon- 

 gate anteroposteriorly. Parietal foramen large. Dermosupraoccipi- 

 tals small or vestigial. Tabulars large, including between them and 

 the squamosal a large otic notch. No supratemporals. Post-temporal 

 openings of considerable size. Ectopterygoids distinct. Spines of 

 vertebrae small. Two or three sacrals. Coracoids free in maturity. 

 No cleithrum. Astragalus and calcaneum sometimes fused. Radiale 

 and fifth carpale unossified, also centrale and fifth tarsale, so far as 

 known. Lacrimals small, sometimes excluded from nares. Para- 

 sternals sometimes present. 



