31 
left side of the skull a portion of this dermal border is crushed over against 
the anterior half of the maxilla, but on the right side the relative position 
is well shown (Plate XVIII, figure 1). 
The vomer is a long, thin, vertically placed bone which is united with 
the pterygoids behind, flanked by the palatines anteriorly, and united, in 
front, with a backwardly developed process of the premaxillae. 
The 'palatine (Plate XVIII, figure 1, Pal.) is roughly boot-shaped, 
with the leg of the boot very slender and the top flared out antero-post- 
eriorly into a flange which unites with its fellow on the midline of the palate 
and covers the anterior end of the vomer. The foot of the boot is rela- 
tively large and the broad toe unites with the posterior half of the maxilla 
and the base of the maxillary process which is given off for union with the 
premaxilla. The internal flanges of the palatines meet on the midline, 
but are not co-ossified. When compared with the palatines of Edmon- 
tonia, those of Anodontosaurus are very much reduced and placed far 
forward. They do not unite with the pterygoids. 
The ectopterygoid is a moderately long, thin bone which unites with 
the postero-internal portion of the maxilla and extends backward and 
inward along the anterior face of the external branch of the pterygoid. 
The pterygoid is greatly reduced and situated well back. It consists 
of two wing-like extensions, one of which is produced inward and forward 
meeting its fellow on the midline of the palate, and one of which is produced 
forward and outward to meet the ectopterygoid and maxilla. The united 
portions of the pterygoids underlie the parisphenoid posteriorly and the 
antero-superior tips meet the vomer. Posteriorly, the pterygoid meets a 
process of the quadrate, but it is not possible to state if it has developed 
a third wing or flange for this union. 
The quadrate is a broad, thin bone and is inclined strongly forward 
from its articulation with the squamosal. This forward inclination of the 
quadrate is a result of the great reduction of the mandible. The superior 
portion of the posterior surface is covered by the rather broad paraoccipital 
process. Near the distal extremity a long, thin process is developed inward 
and forward to meet the pterygoid. Near the distal end of the bone the 
external surface meets the quadrato jugal. The large, sub-triangular 
dermal plate which forms the postero-inferior angle of the skull is thor- 
oughly co-ossified with the jugal and quadrato] ugal and extends well 
below the quadrate. The mandibular articulation of the quadrate is 
broad, but very short, being only 13 mm. in fore and aft diameter and 37 
mm. in transverse diameter. It is quite flat transversely, but convex fore 
and aft. 
The occipital condyle is reniform and the height is about two-thirds the 
breadth. The convexity of the articulating surface is rather less than in 
most plated dinosaurs, thus indicating less flexibility of this joint. The 
condyle faces backward and downward. 
lower jaw (Plate XVIII, figure 2) 
The left mandibular ramus is complete and splendidly preserved, but 
the different elements are so thoroughly co-ossified as to make it impossible 
to positively determine their limits. It is more reduced than that of any 
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