68 



Mr. D. M. S. Watson on the 



Very little of either squamosal remains. Other specimens 

 of tlie same family show that in its o:eneral plan it is very 

 similar to that of Diademodon, but probably lacks the groove 

 for the external auditory meatus. Tiie internal ramus runs 

 upward and forward along the front of the tabulare to the 

 parietal and postorbital, the actual junction with the latter 

 bone being destroyed by weathering in this specimen, but 

 clearly shown in otiier members of the family. 



Tiie lower end of this ramus thickens, articulates with the 

 outer end of -the opisthotic, and supports the lateral ramus, 

 which holds the quadrate. 



Fie:. 3. 



Same skull as tlie preceding figures. Dorsal aspect. " X |. 



Reference-letters as before, with : — Fb., frontal ; Mx., maxilla; 

 P.Fr., prefrontal ; P.Pab., preparietal. 



The parietal is a flat bone on the top of the skull whose 

 posterior end is bent sharply down and overlapped by the 

 interparietal. The bone articulates with its fellow by a long 

 median suture, which is interrupted anteriorly by the pineal 

 foramen, which lies entirely between them. In addition the 

 bone articulates with the preparietal, frontal, postfrontal, 

 postorbital, squamosal, and interparietal, never entering into 

 the border of the temporal fossa. 



The preparietal is very clearly shown as a median lozenge- 

 shaped bone surrounded entirely by the parietals and frontals. 



The frontals are separated by suture ; they are imperfect 

 anteriorly, but articulate behind by jagged sutures with the 



