90 MEMOIRS OF THE CARNEGIE MUSEUM 
The matrix in this region has not been sufficiently removed to show fully 
the inward extension of these plates. The surface of each plate is covered with 
lines that radiate from the center of the plate inward and outward to either 
lateral border. 
The ring is nearly circular in form and almost fills the large orbit. The pupil- 
lary opening measures about 100 mm. in diameter, the entire diameter of the ring 
being 202 mm. The left orbit of No. 603 has the ring nearly as well preserved, 
though the exact number of plates cannot be ascertained. The outer surface is 
inclined somewhat from the center to the outer margin and does not present so flat a 
surface as observed in a specimen (No. 877) of /. communis in the collection of this 
museum. The sclerotic rings do not stand parallel to one another but are inclined 
inward anteriorly. 
Jugal (j.). — The jugal is a long curved bar that forms the lower boundary of the 
orbit. This element in both of the specimens under consideration is unusually 
strong. Anteriorly the end commences in a tapering point which is wedged in _be- 
tween the lachrymal and maxillary. Medially it widens into a subcompressed bar 
reaching its maximum width under the middle of the orbit. At this point supe- 
riorly the surface is slightly concave but becomes flattened and compressed poste- 
riorly terminating in a wedge-like end which is received between the postorbital and 
quadratojugal. 
Parietals (pa.). —In both skulls the median parietal sutures are entirely obliter- 
ated. The lateral surfaces which form the outer walls of the brain case are smooth, 
slightly concave antero-posteriorly and gently convex from the crest downward. 
The matrix has not been sufficiently removed from the temporal fossa to show the 
depth of the parietals or their relations to the lower bones of the brain case. The 
brain case is narrowest just posterior to the middle region but expands both poste- 
riorly and anteriorly. The parietal foramen or pineal eye appears to be bounded 
posteriorly by the parietals and anteriorly by the frontals. Extending forward and 
outward from the lateral boundaries of the foramen are the sutures (?) that unite the 
parietals with the two small frontals. From the antero-internal angle of the tem- 
poral fossa the suture between the postfrontal (?) and parietal extends inward and 
forming an acute angle with the fronto-parietal suture. 
The sagittal crest is indicated by a faint ridge posteriorly. The lower posterior 
border of the parietal rests upon the underlying supraoccipital without sutural junc- 
tion. ‘The posterior lateral extensions curve downward and backward descending 
to the top of the exoccipitals, thus contributing to the upper and lateral faces of the 
occipital surfaces. Seen posteriorly the median portion is slightly thickened, the 
