174 MR. D. M. S. WATSON ON THE 
description of the occiput has yet been published, and I am not 
sure that I understand rightly the figure of that region. 
Apparently, however, that type resembles Dzadectes in the 
closure of its posttemporal fosse by the tabulares extending 
downwards to meet the whole of the opisthotic and supraoccipital 
border, and the supraoccipital is spread out into a wide plate. If 
this is so, the type can have no more than the most remote 
relationship to Pariasaurus. 
Labidosaurus and Captorhinus resemble Pariasaurus in the loss 
of the temporal bones except the squamosal, and in the preservation 
of the posttemporal fosse. They differ, however, completely in 
the primary loss of the otic notch, the bending down of the opis- 
thotics till their outer ends are near the condyles of the 
quadrates, and in the placing of the postparietals vertically on 
the back of the skull. They also seem to differ in the loss of the 
sphenethmoid or any ossification of that character. 
In the postcranial skeleton they differ in having lost the 
cleithrum, and in their curious humerus, which is quite different 
from that of Pariasawrus; and also in the presence of abdominal 
ribs and in the retention of an unspecialised pelvis. 
Too little is known of Pantylus to make a comparison of any 
value. : 
I postpone any comparison with Procolophon until I describe 
that form. 
In the foregoing comparisons I have laid great stress on the 
characters of the occiput and brain-case generally. J have done 
so because a study of this region in material representing nearly 
all the large groups of Reptiles and large Stegocephalia has con- 
vinced me that it is really one of the most important regions of 
the animal from a taxonomic standpoint. 
It is in direct relation with the brain, and the general trend of 
paleontological thought seems to be tending to the view that the 
important part of evolution takes place in the brain, other 
characters following after. In addition this region houses the 
ear, and is far more removed from the action of external con- 
ditions than are such features as the palate and the temporal 
region. It is well known that in mammals the otic region and 
the base of the skull are of great importance in determining 
relationships for precisely this reason. 
Since the time of Seeley most authors have felt that Paria- 
saurus might have some connection with Therapsid ancestry. 
This view was founded mainly on the extraordinarily mammalian 
appearance of the pelvis, where, although there is no pubo-ischiac 
