30 
When viewed from below the skull (Plate XVIII, figure 1) is broadly 
rounded in front and the anterior half is about the same breadth as the 
muzzle. From a point just below the anterior edge of the orbit, which 
is about the midlength, the skull broadens very rapidly. This broadening 
is due to the flaring out of the large plates which cover the lateral temporal 
fossae and quadrates. 
The palate is flat or slightly arched upward, thus differing from 
Edmontonia longiceps in which the pterygoids and palatines unite to form 
a sharp ridge which extends well down into the mouth cavity. 1 A portion 
of the right premaxilla was eroded away and the specimen is somewhat 
crushed, but all the elements are preserved on one side or the other. 
The limits of some of the bones cannot be positively determined owing to 
co-ossification or poor preservation of the bones. The fact that very 
little has been done in the way of description or illustration of the palate 
of the plated dinosaurs makes it difficult to compare Anodontosaurus with 
other forms. There are several fenestra in the roof of the mouth, made 
by the union of branches of the premaxillae, maxillae, and palatines with 
each other and the vomer. In this respect it is very unlike Edmontonia 
longiceps in which there is only one pair of openings in the roof of the 
mouth, viz., the anterior palatine vacuities. 
The internal nares seem to have been wholly within the premaxillae. 
This is an unusual position for the internal nares and it is possible that the 
respiratory canal may have been separated from the mouth cavity in this 
region by a membrane only and that the outlet was through one of the 
fenestra farther back, though this is not considered probable. 
The premaxillce (Plate XVIII, figure 1, Pmx.) make up the whole of 
the inferior portion of the broad muzzle, but are not developed into a flat 
roof as in Edmontonia. The inferior edges of the premaxillae are notched 
and pitted and were covered, in life, with a horn beak, but were not curved 
strongly downward to form a sharp cutting edge as in Ankylosaurus , 
Euoplocephalus, and Edmontonia. The premaxillae are fused anteriorly, 
but farther back the medium separation is well shown. Within the pre- 
maxillae, on either side of the midline of the skull, are the large, sub-oval, 
internal nares. The premaxillae are developed backward, on the midline, 
as a thin process, to meet the long, slender vomer. This union is concealed 
in the specimen by the internal flanges of the palatines, which meet on the 
mid line of the skull, but there is little question as to the premaxillae joining 
the vomer. 
The maxillce (Plate XVIII, figure 1, Mx.) are greatly reduced and 
completely edentulous. The anterior portion of the maxilla is very slender, 
but posteriorly it is expanded into a subcircular, rugose plate about 35 mm. 
in diameter. This evidently served as a grinding or crushing plate. At 
about the middle of the maxilla a slender process, which seems to be a 
branch of the maxilla, runs forward and inward to meet the premaxilla, 
thus forming a fenestra between these two bones. The dermal plates, 
which cover the skull, run straight back from the external borders of the 
premaxillae and flank the posterior portion of the maxillae, but the anterior 
ends of the maxillae are well removed, inward, from these borders. On the 
1 Sternberg. C. M.: “A New Armoured Dinosaur From the Edmonton Formation of Alberta”; Trans. Roy. 
Soc., Canada, vol, 22 (in press). 
