of the Skull in Peloneustes philarchus. 255 
separated from the squamosal (supratemporal of Cope). 
What is here spoken of as the superior ramus of the squa- 
mosal is figured by him as a distinct element, the supra- 
mastoid. No trace of any suture in the position indicated 
occurs in Peloneustes; but since complete fusion with the 
parietal has also taken place, this does not prove that no such 
suture existed. It has already been pointed out that in the 
skull of the young individual of Cryptoclidus recently noticed 
by the present writer in the ‘Geological Magazine,’ June 
1895, the parietals bear postero-lateral processes that cer- 
tainly are not distinct elements, and it is with the posterior 
surfaces of these processes the ends of the upper rami of the 
squamosal unite, overlapping them so far that they nearly 
meet in the middle line behind the parietals.” In Sphenodon 
the upper rami of the squamosal join the front of these 
processes. J am not sure whether, in the young specimen 
mentioned, the upper ramus of the “‘squamosal”’ is not a 
distinct element ; but if this is so, if would seem to show, not 
that the lateral processes of the parietals in Sphenodon are 
distinct elements, but that the ‘‘ squamosal”’ is, as is com- 
monly supposed, a compound bone. 
The ventral ramus of the squamosal is closely united to 
the quadrate, but the exact relation of the two bones to one 
another is difficult to determine. It can be seen that a process 
of the squamosal is closely attached to the anterior surface of 
the quadrate, down which it extends nearly to the condyle. 
On the posterior surface there also appears to be a plate of 
bone, the lower edge of which forms a rounded curved ridge 
a little above the condyle; but it is not quite clear whether 
this is a distinct bone or a process of the squamosal. 
I have not been able to determine whether the small 
quadrato-jugal described by Williston and Cope in Cimolio- 
saurus 1s present or not. 
The quadrate is a stout, massive bone which in its natural 
position seems to have been directed rather outwards and 
backwards. Internally it is supported by the backward pro- 
longation of the pterygoid, which unites with it by suture ; 
externally it is rigidly fixed by the extensive overlap of the 
squamosal. Moreover, judging from the Pliosaur skull 
referred to above, it was further supported by the paroccipital 
process, the outer end of which unites either with the upper 
end of the quadrate or with the portion of the pterygoid 
immediately adjoining. Between the paroccipital process and 
the post-temporal bar there must have been a post-temporal 
fossa of considerable size. 
The condyle for the mandible is transversely elongate and 
LS* 
