170 MR. D. M. S. WATSON ON THE 
temporal bones, the squamosal. In the majority of types the 
pterygoul and squamosal meet behind the quadrate, often in a 
long suture. 
The other two bones never in my experience haye any relation 
with either the quadrate or the pterygoid, 
Dr. Broili’s figures and descriptions of the type skulls of 
Seymouria bayloriensis show that that remarkable reptile is iden- 
tical in the structure of the temporal region and the relations of 
the quadrate with such an amphibian as “ Loxomma,” a con- 
clusion that I have verified by a personal examination of the 
Munich material. ' 
‘The single temporal element in Pariasaurus is articulated with 
the outer edge of the quadrate and sends a process inward along 
its upper border, which in No. 49426 seems definitely to meet the 
posterior ramus of the pterygoid.. Their relations are utterly 
different from those held by the upper two temporal bones in 
Stegocephaha and Seymouria, whilst they are very easily derived 
from those of the lower temporal element of these more primitive 
types by the reduction of the part of the squamosal which 
formerly covered the posterior surface of the quadrate. 
It thus seems that we are justified in identifying the temporal 
element of Puriasaurus with the lower and outermost of the three 
of primitive Cotylosaurs, 
This element is, I believe, the mammalian squamosal, a thesis 
which will be discussed in connection with the Deinocephalian 
skull. 
One curious feature of the Pariasaurus squamosal, the pro- 
jection of a flange of that bone behind the quadrate, is probably 
to be accounted for by supposing that the bone formerly finished 
at the quadrate, leaving a very large otic notch which was sub- 
sequently reduced to its actual minute dimensions by the 
production of the flange. 
Systematic position and Relationship of Paviasaurus. 
The first author who treated of the systematic position of 
Pariasaurus with the use of adequate material was H. G. Seeley 
in 1888. In that paper he reached the conclusion, very novel for 
its time, that Puriasaurus resembled Amphibia, Reptilia, and 
Mammals in different characters, and was intermediate between 
them. Although much of the evidence on which this conclusion 
was based has been shown to be ineorrect, the conclusion itself 
remains remarkably near the truth. 
All recent authors agree in placing Pariaswurus amongst the 
Cotylosanria, an attribution the meaning of which will now be 
discussed, 
The Group Cotylosauria was founded originally on an erroneous 
interpretation of the character of Diadectes, which is the typical 
form of the group. As extended and used by all modern authors 
