THE MOST PRIMITIVE KNOWN REPTILE. 



269 



opens out from the basisphenoid. A broken face about 5 mm. in 

 advance of the tubera shows that in that region the basisphenoid 

 is a thin plate scarcely a millimetre thick medially, 



Text-fieure 1. 



Seymouria hayloriensis Broili. — Restoration of the palate, X f . 



General shape and palate from the types in Munich. Details of maxillary dentition 



from fragments in my possession. Basisphenoid and occipital region from 



mj' skeleton. 

 Reference letters -.—B.Oc, basioccipital ; B.Sp., basisphenoid; Ect.Pt., ectoptery- 



goid; Ex.Oc.,exoccipital; Mx., maxilla ; P.Mx., premaxilla; Pal., palatine ; 



Par.Oc, paroccipital ; Pr.O., prootic ; Pk.V., prevomer; Qu., quadrate; 



X, autogenous basipterygoid process ? 



Parasphenoid. — The parasphenoid is well shown_ in Munich B 

 as a short narrow rostrum projecting forward in the palate 

 between the pterygoids. 



The type of Conodectes shows that it supports a large ethmoidal 

 ossification which surrounds the anterior part of the brain. 



Exoccipitcd. — The right exoccipital is well shown in my skull, 



