SKULL OF A PARIASAURIAN REPTILE, 159 
The front border of the prootic forms a smooth curve with a 
notch at the bottom for the exit of the Vth and VIth nerves. 
The supraoceipital part of the brain-case is produced upward 
as a very massive process of roughly quadrangular section 
channelled and grooved vertically and fused with the postparietals 
over a large area. This separates the large posttemporal fossie. 
Text-figure 2. 
B.S. 
The cranium of “ Pariasaurus,” the Hottentots Rivier specimen, in 
sagittal section, X 4. 
Reference-letters as before. 
The Sphenethmoid.—The anterior part of the brain is surrounded 
by a single bone, which I can only compare with the sphenethmoid 
of a frog. 
Posteriorly, on either side of the pineal foramen, this bone 
forms a flat thin plate which thickens and turns inwards as it 
passes downwards until it unites with the side of the basisphenoid 
above the pituitary fossa. In this region the brain-cavity is 
roofed solely by the parietals, but farther forward the cavity of 
the sphenethmoid contracts very much, and the bone becomes 
quite continuous over the brain: in this region the bone is 
massive although of very loose texture. Farther forward the 
cavity suddenly widens. 
The thick floor is directly continuous with the parasphenoidal 
rostrum, from which it is not visibly separated by suture (49426). 
