274 
PKOFESSOK H. G. SEELEY ON THE STRUCTURE, ORGANIZATION, 
Betliulie, presented by Heer H. S. Viljoen, which is deeper and relatively shorter 
than other known jaws, and has the anterior tooth or teeth remarkably long. 
The Palate .—The base of the skull is occupied by a large oblong median ossification 
in the position of the basi-sphenoid, which is 13 millims. in length, is traversed by 
a deep wide median longitudinal channel, is slightly concave from front to back and 
concave at the sides, so that the width in the anterior part of the bone is half a 
centimetre and it terminates in a pair of stroug prominent tubercles, directed outward 
and forward, which give attachment to the pterygoid bones. The transverse measure¬ 
ment over them is 9 millims., and there is a saddle-shaped anterior concavity between 
these tubercles. 
The posterior end of the basi-sphenoid is not perfectly exposed, and there is a 
possibility that it includes in its posterior part a basi-occipital element, but, if so, the 
suture is obliterated by ossification, as in the skull section figured (Plate 9, fig. 2), and 
it terminates in a pair of articular processes. At the posterior extremity of the median 
groove there is a small ossification extending convexly backward, but this is probably 
a sub-vertebral wedge bone of the atlas, such as is common in Ichthyosaurs, Plesiosaurs, 
and other Keptiles. From this angle a bone, partly destroyed, which I do not identify, 
extends outward and upward. 
In front of the basi-sphenoid is an indication of a slight pre-sphenoid ossification, 
extending u.pward and forward, seen in an almond-shaped vacuity, 7 millims. long and 
4 mdlims. wide, pointed in front and rounded behind, the sides of which are formed 
by the pterygoid bones. 
The pterygoid bones are large ossifications of tri-radiate form. Each sends a flattened 
process backward and outward to unite with the pterygoid process of the quadrate ; 
this is 3 millims. wdde and about 1 centim. long. There is a wude angular vacuity 
between it and the basi-sphenoid, 'which opens backward. Another angular vacuity 
opens laterally between it and the massive transversely extended part of the hone 
which descends so as to be almost in contact with the coronoid element of the lower 
jaw. The transverse width posteriorly over each of the processes is about 1 centim., 
and the antero-posterior extent may be as much. The external part of this process is 
crossed by a line Avhich may indicate an external ossification wdiich w'ould be the 
transverse bone. Anteriorly to these processes the bones converge forward, and unite 
by suture in the median line for a length of about 3 milhms. The extreme antero¬ 
posterior extent of the bone is about 2 "2 centims. The transverse processes are 
directed strongly downward at their outer and posterior margins. On the rounded 
border of the almond-shaped pterygo-sphenoid vacuity there is a row- of pterygoid 
teeth, so placed that they diverge backward in a V-shape. The teeth have all been 
uroken away, but I count the basal attachments of seven on each side. 
In front of the anterior parts of the pterygoids are a narrow pair of bones wdiich 
are not completely exposed anteriorly and only seen for a length of 9 millims. The 
transverse width over both does not exceed 5 millims. They are in contact throughout 
