OSTEOLOGY OF POLYGLYPHANODON—GILMORE 239 
pterygoids develop robust downwardly projecting processes that 
articulate by squamous sutures on the external sides with the strongly 
developed ectopterygoid (ecpt) bones, which are interposed between 
them and the maxillaries (ma) as shown in figure 19. 
The sutural contact of pterygoids and palatines is by a diagonal 
suture that starts at about midlength of the pterygomaxillary vacuity 
(ptmev) and extends inward and forward toward the median line. 
The palatines appear to be narrowly separate on the midline, at least 
posteriorly ; anteriorly they may have been in apposition, as in Jguana. 
Anteriorly the palatines are relatively slender and join the vomers by 
a long diagonal overlapping suture. Posterior to midlength the right 
palatine develops a thin outwardly directed process that laps along the 
Ficure 19.—Palate of Polyglyphanodon sternbergi Gilmore, U.S.N.M. No. 15477, type, 
natural size: bsp, Basisphenoid; bspr, basioccipital process; ecpt, ectopterygoid; exo, 
exoccipital; inpiv, interpterygoid vacuity; 7, jugal; mx, maxillary; occ, occipital condyle; 
pal, palatine; #!nz, palatonarial vacuity; pmx, premaxillary; pt, pterygoid; pimxv, pterygo- 
maxillary vacuity; gu, quadrate; v, vomer. 
inner side of the maxillary. This process forms the posterior bound- 
ary of the palatonarial vacuity. 
The vomers (wv) are distinct but closely applied to one another along 
the median line. Their forward ends are received in a concave notch 
on the posterior sides of the premaxillaries. Laterally, forward of 
the constriction, they also appear to be in contact with the maxiilaries, 
as shown in figure 19. There are five important vacuities in the bony 
palate. The interpterygoid vacuity (inptv) is a single median aper- 
ture, bounded laterally by the pterygoids, and probably extending some 
way between the palatines; posteriorly it is bounded by the hypophyses 
of the basisphenoid. The pterygomaxillary vacuity in Polyglyphan- 
odon, as contrasted with those of 7guana, are much reduced in size. 
