BONES OF THE CRANIUM 135 
They constitute the upper part of the posterior wall, bend sharply forward along 
the lateral wall, and enter into the formation of the temporal fossa. The line of 
inflection is marked by the prominent parietal crest, which is continuous with the 
temporal crest below and the frontal crest anteriorly. The parietals are excavated 
to form part of the frontal sinuses in the adult animal. 
Frontal Parietal 
eminence bone Processus 
< cornus 
Parietal 
crest 
Temporal 
fossa 
Zygomatic arch ee : 
Supraorbital foramen 
Frontal bone Supraorbital groove 
Orbit 
i ys B \ ig Malar bone 
ay ’ ‘- 
La Lacrimal bone 
is 
4 
> 
‘, 
%, 
w 
Mazilla 
Facial tuberosity 
Nasal bone 
Nasal process of premazilla 
-,! Palatine process of premazilla 
Palatine fissure 
Body of premazilla 
Fic. 133.—SkuvLt oF Jersey Cow; Dorsat VIEw. 
The condition in the young subject is as follows: The two parietals are united with each other 
and also with the interparietal and supraoccipital. The resulting mass is somewhat horseshoe- 
shaped. Its occipital part (Planum occipitale) forms the greater part of the posterior wall of 
the cranium and bears about its center the tuberosity for the attachment of the ligamentum 
nuchez. From either side of this a line curves outward and divides the surface into an upper 
smooth area and a lower area which is rough for muscular attachment. The upper border joins 
the frontal bone and concurs in the formation of the frontal eminence. The temporal parts 
(Plana temporalia) are much smaller and are concave externally; they join the frontal above and 
the squamous temporal below. A median occipital crest extends ventrally from the external 
occipital protuberance. 
The frontal bones are very extensive, forming about one-half of the entire 
