472 



PEOF. H. G. SEELEY ON DELPHII^OGNATHIJS CONOCEPHALTTS. 



prolonged downward by the post-frontal bone wbich forms tbe 

 hinder border to the orbit. The bone twists as it descends, so that 

 its lower extremity, which has lost the inflation of its upper part, is 

 nearly in the same plane with the squamosal bone. It is from 2 to 

 2'5 centim. wide. There is an excavation behind its posterior angle, 



Pig. 2. — View of upper portion of Skull of Delphinognathus. 



^ nat. size. 



= occipital margin. 



s = squamosal bone. 

 pt = post-frontal bone. 

 or = margin of orbit. 



/ = frontal bone. 

 t = temporal vacuity. 

 p = parietal foramen. 



where it meets the squamosal bone, and this gives a sharp posterior 

 margin to the post-frontal bone. The squamosal bone contributes 

 to the hinder part of the inferior border of the orbit ; while the malar 

 bone forms a narrow bar on the antero-inferior border of the orbit. 

 It meets the squamosal behind, and is prolonged downward and 

 backward below the squamosal, terminating above the supra- 

 condyloid notch ; anteriorly it presumably meets the maxillary bone, 

 but the suture is not evident. The squamosal bone, which is im- 

 perfect posteriorly, is of a sub-rhomboid form as preserved, with a 

 talon extending downward and forward to cover the condyle formed 

 by the quadrate bone. It is flattened on the vertical external 

 surface. The infero-posterior outline is nearly straight, becoming 

 concave towards the quadrate condyle, and, as preserved, is about 

 11 centim. long. The oblique transverse measurement from that 

 border, which is rounded from within outward, to the orbital margin 

 is about 7*5 centimetres. 



The condyle is about 4 centim. deep, but behind the vertical 

 articular surface the bone is a little constricted from above down- 



