242 PROCEEDINGS OF THE NATIONAL MUSEUM VOL, 92 
available specimens have been obliterated. Anteriorly it meets the 
dentary and splenial. 
Articular.—The articular (ar) forms the entire angle of the jaw. 
The end posterior to the cotylus is gently incurved and has a bluntly 
truncated termination. Viewed externally the whole surface from the 
top downward strongly recedes inward. The upper border imme- 
diately posterior to the cotylus is deeply concave. The cotylus is 
shallowly concave anteroposteriorly, bifossate. It has a greatest 
width of 7.5mm. Most of its outer wall is formed by the surangular. 
Splenial—The splenial (sp) is a thin triangular shaped bone that 
laps along the lower inner side of the dentary. Its pointed anterior 
extremity ends short of the symphysis. Except at the anterior end 
it completely covers Meckel’s groove and in a lateral view is not 
Ficure 21.—Right ramus of Polyglyphanodon sternbergt Gilmore, U.S.N.M. No. 15568, 
superior view, natural size: a7, Articular; c, coronoid; d, dentary. 
visible on the lower border. A foramen perforates its upper median 
border. The large size and great anteroposterior extent of the 
splenial in Polyglyphanodon shows a striking distinction from the 
small, limited splenial of Cyclura and Iguana or the very small 
splenial found in the Agamidae. 
Prearticular.—Although the prearticular is indicated in figure 20, 
T have been unable to delimit its boundaries. 
Measurements—The measurements of the ramus of the type, 
U.S.N.M. No. 15477, are as follows (in millimeters) : 
Greatest lengths: -- 22 te Se Se ee Sa a ee 85. 5 
Greatest depth at posterior’ end. of toothtrowe2s2) ee eae ne ee 16.5 
Depthcvor ramusiat anterior endt 2! ase see ee ee eee 5A) 
Depth of ramus;to/top of coronoid=2 ais =i ae ee eee 24.3 
Transverse width, at) middie, of, tooth jSeries 2a ene Se 5 
Differences.—The splenial is very small or absent in the Agamidae, 
and the dentary has the greatest posterior extent in the Chamaeleon- 
idae and Agamidae, either being a feature that would disbar Poly- 
glyphanodon. The Meckelian grove is open in Chamaeleonidae, Aga- 
midae, and Varanidae but is roofed over more or less completely in 
all other families, as it is in Polyglyphanodon. 
TEETH 
The outstanding feature of Polyglyphanodon sternbergi is the 
transverse widening of the teeth of the posterior half of the dental 
