126 J. Hi. LEES 
is exposed by the breaking away of the outer bony cover for at least 
one and one-fourth inches they must extend somewhat further beyond. 
As is the case with the premaxille, and indeed with all the bones 
‘of the roof of the skull adjoining the median line, the median suture 
remains distinct. The nasal septa are plainly separate and the 
suture may be readily distinguished along the whole length of the 
skull as far as the supraoccipital where it becomes indistinguishable. 
The nasal has not a very wide lateral extent, but if the boundaries 
as indicated in describing the maxilla are correct, it is limited to the 
upper part of the skull and has nowhere a width of more than one 
and one-half inches, although its extreme length is probably about 
nine inches. It is somewhat elevated around the naris, and so 
raises this opening slightly, and it is excavated for nearly its entire 
depth opposite the anterior half of the naris, leaving this open to the 
side for a depth of fully one inch. In life this lateral space was 
doubtless covered by the integument, confining the nostril to the 
upper surface of the skull. Whether or not the nasal reaches the 
antorbital vacuity is not certainly known, but it very probably does 
so for a short distance, perhaps from one-half to one inch, between 
the lachrymal and the maxilla. 
Frontal.—Behind the nasal on the roof of the skull is the frontal, 
a long, narrow, subrectangular bone nearly four inches in length 
which unites with the nasal by a strong, splintery suture. The bone 
extends as far as the posterior limit of the orbit, a part of whose 
superior margin it forms. It is ornamented with irregular, longitu- 
dinal grooves and ridges on its anterior portion and by shorter pits | 
and rugosities in the central and posterior regions. 
Prejrontal—This is also long and narrow, but is less regular in 
outline than the frontal. It is limited behind by the orbit and extends 
forward slightly beyond the frontal, where it terminates bluntly and 
is inserted into a notch in the nasal. 
Lachrymal.—Between the prefrontal and the maxilla lies the 
lachrymal, a broad, irregularly shaped bone which forms the upper 
part of the arch between the orbit and the antorbital vacuity. Both 
of these openings penetrate this bone somewhat from front and rear, 
so that on the line between them it is constricted to a relatively narrow 
isthmus. The main body of the lachrymal gives off a slender anterior 
