CORYPflODON. 
219 
The supraoccipital region is deeply concave, owing to the production back¬ 
ward of the lateral and superior walls of the cranial chamber. 
With the cranium in the position described, the occipital condyles present 
partly upward. The united mastoid and paramastoid processes present a 
wide posterior face, and descend to the line of the inferior face of the con¬ 
dyles. The postglenoid process is large, but not very wide, and descends 
a little below the mastoid. The zygomatic process of the squamosal expands 
abruptly outward at the glenoid cavity, and its superior border is continued 
posteriorly external to the line of the postglenoid process, thus roofing over 
the external auditory meatus. The external face of the zygomatic process 
is convex and incnrved above. The malar portion of the zygoma, just after 
leaving the maxillary bone and opposite to the last molar tooth, presents 
downward a truncate tuberosity, which has considerable antero-posterior 
extent. The orbital space is contracted by an expansion of the cranial 
walls outward and upward in the position of the superciliary horn of the 
Loxolopliodon cornutus. This must have caused the eye to protrude, if it 
were of ordinary proportions. A small rugose tuberosity projects outward 
on the lachrymal bone. The foramen infraorhitale exterius is of moderate 
proportions, and opens over the third premolar. 
The superior walls of the skull are so coossified as to obliterate all 
sutures. Anteriorly, the surface is nearly smooth; toward the middle, it is 
marked with shallow impressed grooves and dots; while, in its posterior 
half, it is so roughened by shallow pits and wrinkles as to resemble corre¬ 
sponding parts in some Crocodiles and other Saurians. Doubtless in life 
this part of the skull was, as in Reptiles, only covered by a thin epidermis. 
The superior surface of the skull is, above the lateral contraction and in 
line with the canine alveolus, swollen into a convexity which represents the 
middle corneous process in Uintatherium. These are followed by a con¬ 
cavity, behind which rises on each side the supraorbital tuberosities already 
described, which are larger than the anterior ones, and are separated by a 
longitudinal concavity. These tuberosities are continued posteriorly as low 
ridge's, which unite a little behind the position of the orbits into a central 
ridge. This is bounded on each side by a marked longitudinal concavity, 
which begins anteriorly at the margin above the posterior part of the orbit. 
