AND CLASSIFICATION OF THE FOSSIL REPTILIA. 
241 
towards the quadrato-jugal bone. Moreover, it would correspond in plan to the 
quadrate of llatteria, except that it rather resembles Ichthyosaurus in the absence of 
a pterygoid process, in the wedge-like supra-condylar mass, and its superior termina¬ 
tion in a sharp margin. The divergence of character, in which it varies from the 
quadrate of other Anomodonts, and approximates to Ichthyosaurus, would warrant 
its reference to a new genus. 
On a somewhat crushed and imjDerfect Shull of Dicynodon Copei, Seeley. 
(See Plate 14.) 
The skull numbered 47,074 is distorted, but indicates a new species of Dicynodon, 
which appears to resemble the type named by Professor Cope Lystrosaurusf in which 
the face is vertical to the superior surface of the head. The nares approximate as 
closely as possible without being confluent, are circular, and inferior in position to the 
large circular orbits, which are posterior to the nares. The large teeth descend 
vertically. 
The palate has been very fully excavated (flg. 3), and shows the wide smooth surface 
of the basi-sphenoid, slightly concave from side to side, and less convex from back to 
front. At each side, stretching between it and the quadrate bone, is the pair of bones 
with saddle-shaped surfaces, originally figured! in Dicynodon lacerticeps (Owen), and 
already recognized in other Dicynodonts. In a line with their anterior margin the 
irregular transverse suture is seen, which marks the overlap of the pterygoid upon the 
basi-sphenoid. The lateral surfaces of this mass converge forward to make deep 
notches, external to which the quadrate processes of the pterygoid are prolonged out¬ 
ward and backward as thin oblique plates, which reach the external borders of the 
sub-quadrate saddle-shaped bones already referred to, which are regarded as the 
malleus. In front of these, the quadrate processes of the pterygoid bone are considerably 
constricted ; and then an anterior pair of processes diverge forward and outward, so 
as to terminate behind the maxillaiy teeth, where a thin plate of the maxillary over¬ 
laps the pterygoid externally, but only on the upper part of the anterior process. In 
the constricted middle plate of the pterygoid is a long median vacuity, lanceolate 
behind, and tapering in front to a slender point. It is defined laterally by very 
slender plates, which converge inward and forward to form a single median plate, 
reaching forward to the maxillary region; and this plate may probably be identified 
as the vomer. 
Stretching along the inner side of each anterior bar of the pterygoid is the palatine 
bone, which widens as it extends forward, so as to enclose with the slender V-shaped 
vomerine plate a pair of long oval vacuities in the palate, which I regard as the 
* ‘ Amer. Phil. Soc. Proc.,’ vol. II, 1870, p. 419. 
t ‘ Geol. Soc. Trans.,’ 2nd Series, vol. 7. 
2 I 
MDCCCLXXXTX.—B. 
