MORPHOLOGICAL REVISION 



93 



The postfrontals are not well known; the sutures of the posterior ends 

 have not been made out. 



The postorbital is a small triangular element between the postfrontal, 

 jugal, and prosquamosal. 



The jugal is elongate, reaching from the maxillary and lachrymal in 

 front, nearly or quite to the posterior edge of the skull. Branson figures it 

 as excluded from the posterior part of the outer edge of the skull by an 

 elongate quadrate, but in specimen No. 4673 Am. Mus., in which the sutures 

 of the lower surface are clearly shown (plate 7, fig. i), the quadrate appears 

 as a very short element, taking part only in the extreme posterior part of the 

 edge of the skull, and the quadratojugal reaches nearly to the posterior end. 

 The jugal forms the lower edge of the orbit. 



Fig. 26. — Skull of J?ryo/ij sp. No. 4310 Am. Mus. X ?. 



A. Upper view, showing sutures as far as they can be made out. sm, septomaxillary. 



B. Lateral view of same specimen shown in A. 



The prosquamosal forms the bulk of the posterior angle of the skull. 

 The inner side is smooth and the outer surface is marked by a peculiarly 

 coarse sculpture. The bone showing below the prosquamosal on the inner 

 side is not the quadrate, as suggested by Branson, but the posterior end of 

 the pterygoid. 



The outlines of the parietals, squamosals, and tabulare are uncertain; 

 the latter element has not been proven to exist, but is probably present. 

 Contrary to Branson's statement, a parietal foramen is present, though it 

 is small compared to the size of the skull. 



The supraoccipital plates are small and form the posterior edge of the 

 skull. 



The lower surface of the skull is shown almost perfectly in specimen No. 

 4673 Am. Mus. (plate 7, fig. i). This skull was found in a loose, sandy gravel, 

 and the matrix fell away easily from the bones, leaving them naturally clean; 

 the sutures are as readily traced as in a recent skull. Unfortunately, the 



