The _Premaxillary_ is rather short and stout; it is slightly
compressed, and ends in a sharp keel on top. Although not so thick
as in _Palæosyops_, it is much larger vertically. The inner surface
is ridged; it has no palatine process, and no spine, so that the
incisive foramen is large and undivided. There was no symphysis
between the two premaxillaries, they do not show even any articular
faces for each other, so that they may not have been in contact
during life. The animal was adult, but not old. The incisive alveolus
is short and straight, and is but little out of the line of the
molars. There is a very long diastema between the incisors and the
canine, and here the premaxillary is deeply notched to allow the
passage of the lower canine.
The _Malar_ is very different in shape and size from the same bone in
_Palæosyops_. Its facial extent is greater, as it articulates with
the maxillary as far forward as the first molar. It is not so broad
from above downwards, but is considerably thicker; the articulation
with the squamosal is by flat surfaces. The postorbital process is
small and indistinct. The orbit is of great size; its breadth, shown
by the maxillary floor is unusual, but its fore-and-aft diameter is
extreme, being nearly twice as great as in a large _Palæosyops major_.
The _Squamosal_ is a short, slender, and trihedral bone; it is not
at all like the squamosal of _Palæosyops_. It is smaller even than
that of _P. paludosus_; its outer margin is not turned up, making the
upper surface concave; it does not project much outward, and scarcely
at all downwards, as this is rendered unnecessary by the flatness of
the forehead. The chief difference, in the size of this bone, between
this genus and _Palæosyops_ is found in the much greater vertical and
lateral diameter of the latter; in length they are about equal. The
glenoid cavity is large, shallow, and transverse.
As a whole, the zygomatic arch is comparatively slender; it is
rounded, and does not project much laterally from the side of the
head; but its chief peculiarity consists in the fact that it is
nearly horizontal. It is thus altogether different from the arch of
_Palæosyops_.
The _Occipital Condyles_ are different from those of that genus.
They are flatter, shorter from above downwards, and proportionately
much smaller; but are expanded laterally in much the same manner. At
the border of the foramen magnum they are gently rounded instead of
having a sharp angle. These borders are segments of circles, but as
the condyles are broken from the rest of the occiput, we cannot infer
from this the shape of the foramen.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account