146 KANSAS UNIVERSITY QUARTERLY. 
Fig. 3.—Skull of Xerobates undata Cope, natural size. 
side also deep. The maxilla does not curve inward anteriorly to 
meet the premaxilla, but is rounded in this region by thinning to a 
sharp edge. The inner edge of the maxilla makes a low, almost 
serrate border, becoming lower anteriorly until it merges into the 
level bottom of the inner channel. 
The palatine foramen is situated near the sutural union of the 
palatine and pterygoid. There is a strong ridge below the foramen 
and, on either side, a narrow, shallow grove. The pterygoids have 
the anterolateral sides projecting as long, narrow, rod-like processes, 
standing at an angle of thirty-three degrees with each other. They 
unite for a short distance between the basisphenoid and vomer 
deepening anteriorly the palatine region. The lateral edges ap- 
proach each other to just behind the anterior end of the basi- 
sphenoid, where they diverge gradually, becoming less prominent, 
and finally terminating in the postero-lateral process. The vomer 
has very irregular margins and a medial ridge throughout its entire 
length, except at the anterior end, where a small, deep, narrow, 
U-shaped groove occurs. Anteriorly the vomer sends down a 
strong, triangular column, the anterior surface of which is deeply 
and angularly channelled. The jugal is an hourglass-shaped bone, 
and is very light. The quadrato-jugal is a much wider bone than 
the jugal. It is broad, thin and plate like, expanding anteriorly 
to a width of twelve millimeters, posteriorly to eight. 
The deep external tympanic fossa of the quadrate is oval or 
inverted reniform, with its long axis directed downward and for- 
ward. The squamosal is arched over the tympanic fossa from the 
ee 
