A FOSSIL REPTILE. 739 
One feature of the skull about which there has been some 
dispute is the presence or absence of a foramen in the temporal 
region. There is no doubt that Broom is quite correct in denying 
its, presence, but in justice to Prof. Seeley and the British Museum 
mason, it should be pointed out that the hole in this region in 
their skulls i is not an artifact, but is due to a rotation inwards of 
the posterior edge of the postorbital as a result of slight 
crushing. 
Text-figure 3. 
Procolophon trigoniceps. 
(A) Outer, and (B) Inner aspects of lower jaw. X 1. 
Ang, Angular; Cr., Coronoid; Den., Dentary; P.Art., Prearticular ; 
Sp., Splenial; Sur. Ang., Surangular. 
Composite figures from two specimens. 
The structure of the lower jaw will be understood from text- 
fig. 3. The sutures separating the prearticular from the articular 
and angular are not clear in any specimen, but I think they are 
faintly shown as figured in the skull of the female skeleton. 
Every other suture is obvious. 
The coronoid extends forward between the dentary and splenial 
for some distance. 
Vertebral column.—There are twenty-six presacral vertebre. 
The axis has a powerful spine, very long anteroposteriorly ; and 
powerful posterior zygapophyses, which are continued forwards 
into a broad table. There is a large intercentrum between the 
centrum of the axis and the odontoid. The odontoid is not known 
in detail. 
The atlantal intercentrum is large and its anterior face forms 
part of the cup for the occipital condyle. There is a pair of 
neural arches to the atlas. These are separated posteriorly by 
the neural spine of the axis; each has a facet on its inner face by 
which it articulates with the odontoid, anteriorly it has an 
articular face for the basioccipital. In front its upper surface is 
overlapped by the proatlas, and behind it articulates with the 
