236 



3Ir. \l. j^room on ihe 



But though in front it lias a smooth edge the posterior edge 

 is irregular, as if indicating an ossification in cartilage. The 

 anterior ossification or ossifications ])robal)ly correspond to 

 the sphenethmoid of Sireilon or the frog, and the posterior 

 to the ossification seen in Dinosaurs, Crocodiles, and biids, 

 and usually, but I think wrongly, called alisphenoid. 



The quadrate is large and its upper half is largely hidden 

 by the squamosal. There need not, 1 think, be the slightest 



Fiir. 2. 



.S. Ang 



P.Art. 



Lower jaw of Lysorojihiis trican'nfdii.i, Cope, x 5. A represents a 

 section at a a. 



Any., &uga\&v ; D, dcntary ; P.-i/V,, preaiticular ; S'.An//., Huvaugiil&r. 



Fig. 3. 



S.Anp 



— /Jrttf. 



Section across skull and jaw of Lysoropliup. iricannatns, Cope, X •^. The 

 section of the lower jaw is near the point indicated by b h in tJie 

 figure of the jaw. The outer corners of the paraspht-noid are sepa- 

 rated by cracks or sutures. They are believed to be parts of the 

 parasphenoid. 



yln^., angular ; Prt., parietal ; Pa. 6))., parasphenoid ; P.^?•^, prearticular ; 

 Pt., pterygoid ; S.Any., &urangular. 



doubt about this bone being the squamosal — the view also 

 held by Williston and v, Hueiie. 



The occiput has recently been figured by v. Huene from 

 one of the American Museum specimens and also from one 

 of the Tiibingen specimens. Hisxlrawing of the American 

 Museum specimen is not in my opinion quite accurate, the 

 American specimen agreeing closely with his figure of the 

 Tiilnngen specimen. The main difll'ereiice between the two 



