20 Fietp CotumsBian Musrtum —Geo.tocy, Vou. II. 
from the quadrate is situated as in Crmoliasaurus snowil, at the external 
angle of the quadrate, which it borders to its upper extremity. At 
the lower extremity there is a very distinct squamate suture, running 
upward and forward and becoming lost about twenty millimeters from 
its origin. This suture is clearly apparent on the two sides, and is 
also seen in the skull of Cimoliasaurus snowit, as it was figured by 
myself (l.c.) and Cope*. Just what the course of the suture is 
anteriorly I cannot say, but I believe that it is indicated by a line 
passing forward to the maxilla, and excluding that bone from union 
with the squamosal. Whatever be its relations anteriorly, 1 doubt 
not that the quadratojugal exists as a distinct ossification in the 
plesiosaurs. In a separated quadrate of another species of plesiosaur 
(7. anonymum Will.), from the Benton of Kansas, the sutural sur- 
faces for union with the quadratojugal and squamosal are clearly dis- 
tinguished. The quadratojugal does not enter into the formation of 
the condylar surface of the quadrate, as has been suspected, and as it 
does in Sphenodon,; this is certain. On the outer side of this quadrate, 
just above the articular surface, there are two sutural surfaces—one 
on the posterior and outer border, for the attachment of the squamosal, 
the other on the anterior border for the attachment of the quadrato- 
jugal, which, in this case, as also in Dolichorhynchops osbornt, must 
have been overlapped in part by the squamosal. In Cimoliasaurus 
snow, the suture between the squamosal and’ the quadratojugal is 
very clearly indicated from the exterior, the squamosal not descend- 
ing as low as in the other species. The suture shown as separating 
the quadratojugal from the squamosal anteriorly is conjectural, but I 
believe, as already stated, that it will be found to extend as far for- 
ward as the maxilla. 
The suture separating the squamosal from the postorbital is short 
and vertical, joining the border near the anterior extremity of the 
bone, as seen from the outer side. The suture joining the jugal is a’ 
squamous one, extending on the inner side nearly to the margin of the 
orbit, but leaving a small space for the union of the ectopterygoid 
with the jugal: The suture with the maxilla is long and oblique, con- 
cealed in about half its extent by the jugal. I believe, however, that 
the squamosal is really separated from the maxilla by the intervention 
of the quadratojugal, as already described, and for which there seems 
to be some evidence in the specimen, On the right side the maxilla — 
had been removed by maceration, leaving the sutural surface for the 
temporal element very clear.in its whole extent. 
Posteriorly, the sutural line of the squamosal passes downward 

* Proc. Amer. Phil. Soc. 1894. 
