266 
THE FRONTAL BONES 
membrane, assumes in cattle ; and for the frequent accumulations 
of pus about the root of the horn, and particularly at the pos¬ 
terior part of it. 
The supra-orbital foramen must necessarily, from what I have 
shewn you, open into the frontal sinus, and the nerve and artery 
which supply the forehead must pass through a portion of that 
cavity; and as they have a greater surface to supply, thev are 
considerably larger than in the horse. In fact, there are 
usually two foramina on each side; and as the increased size of 
the artery and nerve would render them more prominent, they 
are lodged in a depression or sulcus, extending both above and 
below, until they divide into smaller branches less liable to injury. 
In the polled variety of oxen, the frontal bones are as exten¬ 
sive as in the horned. They reach from the nasal bones to the 
summit of the head; but the diploe is not so great, although the 
frontal sinuses are considerably larger than in the horse. This, 
however, varies much in the different breeds of polled cattle. 
I shall not enter into a full description of these bones as in the 
horse, but content myself with the points of difference. 
The orbitar process, as you will see in these crania, is not so 
developed as in the horse. It presents a much narrower and 
sharper surface externally, and its breadth is from without, in- 
w ard. It is small and w eak compared with that of the horse, 
because the upper and outer portion of the orbit of the eye is 
defended from injury by its very situation, while it is the part 
most exposed to danger in the horse. When we arrive at the 
temporal fossa, which, in the ox, is low r on the side of the head, 
instead of a portion of it, or the commencement of it being, as it 
w ere, on the forehead, the orbitar process takes a direction down- 
w^ard and forward, instead of downward and backward, and 
abuts upon, not the temporal bone as in the horse, but a 
bifurcation of the malar bone, and does not enter at all into the 
composition of the zygomatic arch. That arch, depressed in its 
situation in the ox,—not requiring much curvature, because the 
food of this animal is gathered more at leisure, and the process 
of rumination is slowiy and sleepingly performed, and there is 
not wanted so much bulk of temporal muscle, nor such extensive 
motion of the coronoid process of the lower jaw—that arch, I say, 
needs not the frontal bone to give it curvature or strength. The 
orbitar process abuts upon, and is united to the upper bifurcation 
of the malar bone, by a suture both squamous and serrated. Its 
union with the parietals—distinct parietals in the ox—is found at 
the summit or ridge of the head, and deep within the temporal 
fossae. 
The greatest variation, however, between the frontals of the 
horse and of most breeds of oxen consists in their prolongation. 
