OSTEOLOGY OF POLYGLYPHANODON—GILMORE 234 
is more massive, and the spurlike process is more extensively 
developed than in any lizard with which I have been able to make 
comparison. 
Squamosal_—Both of the squamosal (sq) bones in the type skull 
are more or less damaged, but the paratype has both well preserved. 
They are relatively short bones, deep dorsoventrally, with a squarely 
truncate posterior end. This end is in contact with the paraoccipital 
process of the exoccipital, the posterior process of the parietal and 
the tabulare, and with them forms the postericr angle of the skull. 
It abuts the paraoccipital process of the exoccipital. On the lower 
side near the posterior end it is hollowed out by the cotylus for the 
articulation of the quadrate. Superiorly it joins the posterior branch 
Ficure 18.—Skull of Polyglyphanodon sternbergi Gilmore, U.S.N.M. No. 15477, type, 
natural size, posterior view: bspr, Basipterygoid processes; exo, exoccipitals; occ, occipital 
condyle; p, parietal; po, postorbital; pt, pterygoid; ptf, postfrontal; gu, quadrate; so, 
supraoccipital; sg, squamosal; za, tabulare. 
of the postorbital by squamous union, thus forming the supratemporal 
arcade. The full course of the squamosal-postorbital suture, as shown 
in figure 16, is derived largely from the evidence of the paratype. 
Tabulare.—The presence of a tabulare (fa) is clearly indicated on 
the left side of the type specimen, where its posterior end is inter- 
calated between the squamosal, quadrate, and paraoccipital process, as 
shown in figure 18. 
Quadrate-—The right quadrate (qu) of the type is in beautiful 
preservation and in articulated position. (Quadrates are also present 
in specimens U.S.N.M. Nos. 15559, 15556, and 15816. Viewed pos- 
teriorly the outer border, which is thickened and roughened, is bowed 
outward from end to end with a wide external conch. This border 
projects backward beyond the level of the adjacent surface. The 
articular proximal end is rounded anteroposteriorly and strongly 
overhangs the posterior surface. A sharp ridge develops at the base 
465455—42 2 
