AND CLASSIFICATION OF THE FOSSIL REPTILIA, 
243 
nvate parietal foramen, ^A'hich appears to he 1 ceiitim. long. At the anterior cornei's 
ot the orhits are narrow pre-frontal hones, crossed hy angular ridges which extend 
forward and separate the flat roof to the snout from the slightly inclined ant-orhital 
wall. The transverse width at the corners of the orhits is 3'5 centims. at 7 centims. in 
advance of the posterior fracture. The roof hones extend for 4 centims. forward in 
advance of this, converging to about 12 millims. wide at the anterior fracture, so that 
the angular ridge which borders the area laterally is slightly concave in length. The 
A’ertical height of the back of the skull in the post-frontal region is about 5'7 millims.; 
anteriorly the vertical depth to the maxillary plate of the palate is a little over 
4 centims. The transverse width at the base of the hinder border of the orbit is 
8 centims., while anteriorly at the maxillary plate it is 4 centims. 
The maxillary hone is very imperfectly preserved, and is best seen on the right side, 
where a part of its inferior palatal border extends backward horizontally towards the 
orbit, but extends belotv it. Its rounded lateral border makes a considerable angle 
Avith the palatal surface of the bone, which is reflected inward and downAvard. In the 
part of the alveolar border which is preserved I can detect no indication of dentition. 
The form of the head Avould have suggested teeth of the Gennetotherioid type, in 
Avhich the incissors are large and the molars small, but so much of the hinder margin 
of the maxillary bone as is preserved only demonstrates imperfectly a cutting margin, 
with doubtful indications of immature teetb buried in the substance of the bone. 
The palate in front is formed by two bones which meet in the median line by a close 
median suture at the bottom of a slight median concavity. These bones curve 
convexly upward in front, are in contact Avith the maxillary bones at the sides, and at 
their hinder outer corners meet the pterygoid bones, so that they appear to demon¬ 
strate the palatine as a transversely ovate plate consisting of tAvo lateral portions. 
The palatine processes of the pterygoid bones are slender plates of almost rod-like 
form, which converge inward as they extend backAvard, but they descend to a loAver 
level, apparently, than the maxillary bones. The exact mode of their union AAuth the 
mass of the pterygoid bones is not evident. But the pterygoid bones unite in the 
median line, where they are unusually elongated, and inclined toAvards each other so 
as to meet interiorly in a median keel. On the right side a process is given off which 
extends transversely outward and upward to the malar region of the base of the orbit, 
though the malar bone itself is clearly defined. This pterygoid process is therefore in 
the position of the transverse bone. The sphenoidal region of the palate ascends, 
and at the fracture is concave from side to side and shoAvs the rounded form of the 
base of the brain-cavity. The inter-parietal bone is seen to extend obliquely over the 
cerebellar region in the usual Avay. 
There is a general resemblance between tbis type of skull and ^^lurosaurus, which 
shows that this genus belongs to the Gennetotherioid diAusion of the Anomodont order ; 
but Pig-like ridges on the snout and other features sufiiciently distinguish it from 
Theriodont genera, and the palate is distinctive. 
2 T 2 
