No. 434] THE AMERICAN PELYCOSAURI A. 



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described and figured but a single arch (Cope '78, '92). The 

 portion marked jugal by him, figure 6, is crossed by a break that 

 seems to me to be very likely along the suture between the 

 quadrato-jugal and the jugal. Posterior to the orbit the bones 

 are badly broken and mixed, but certain parts seem capable of 

 a very different interpretation from that of Prof. Cope. The 

 small fragment labeled post-orbital in Cope's figure seems to me 

 to be a bit of bone from the base of the skull extending out of 

 the orbit. Posterior to the orbit Cope has figured but one piece 

 which he calls the supratemporal ; this appears different to me 

 inasmuch as the anterior edge distinctly shows the rounded 

 excavation forming the posterior edge of the orbit and indicating 



that it is the postorbital bone. Further back the mass bifurcates, 

 this would make the anterior leg of the bifurcation the lower 

 part of the postorbital, a consideration which is borne out by its 

 relation to the upper part of the jugal ; the suture between the 

 two is hidden by the matrix and a fracture. The posterior leg 

 is exactly in the position of the anterior end of the postorbital- 

 prosquamosal arch if the arches had the same depressed form as 



