THE PHYTOSAURIA OF THE TRIAS 133 



the plane of the dorsal surface of the cranium. This will be dis- 

 cussed more fully in connection with the posterior aspect. No 

 parietal foramen is present. 



THE SEPARATE BONES OF THE DORSAL SURFACE 



The parietals are united along the median line for a distance of 

 about 100 mm. Posteriorly they are separated for a short distance 

 by a deep, rounded notch. In spite of this deep incision, however, 

 the occipital condyle is not visible in a dorsal view. Their anterior 

 ends form an acute angle that separates the frontals for a short dis- 

 tance. The greatest width of the parietals, a little in front of the 

 anterior border of the supratemporal fenestrae, is about 42 mm. for 

 each element. The parieto-squamosal suture is not clearly dis- 

 tinguishable; apparently these elements meet on the inner pos- 

 terior borders of the supratemporal fenestrae. 



The squamosals form the posterior and half of the lateral borders 

 of the supratemporal fenestrae and the upper posterior borders of 

 the lateral temporal fenestrae. They are bent abruptly downward 

 at a point on the antero-posterior line of the bar separating the 

 supratemporal and lateral temporal fenestrae, the downward exten- 

 sion being produced into a hooklike process similar to that of 

 Mystriosuchus but with greater development. These hookUke 

 angles extend below the dorsal surface of the skull a distance of 

 about 104 mm. This part of the squamosal and the lower posterior 

 surface of the quadrate as well was weathered away, but a 

 perfect natural mold in the matrix made possible a very accurate 

 restoration. 



The postorhitals form a part of the antero-lateral borders of the 

 supratemporal fenestrae and the postero-lateral borders of the 

 orbits. They extend down and forward to meet the upper pos- 

 terior process of the jugal, and the two form narrow bars that 

 separate the orbits and the lateral temporal fenestrae. The inner 

 boundaries of the postorbitals are formed by the postfrontals and 

 the parietals which meet near the middle of the postorbitals' 

 length. 



The postfrontals are rather small, approximately quadrangular 

 elements that form the posterior half of the upper borders of the 



