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128 ANATOMY OF THE RABBIT. 
structure, articulated with the main body of the skull by a typical 
joint. 
The skull is roughly divisible into two portions, namely, an 
anterior, facial portion, and a posterior, cranial portion The 
cranial portion has a somewhat conical shape, its apex being directed 
forward. It is separated from the facial portion by a depression 
on either side of the skull, the orbital cavity (orbita), which serves 
for the accommodation of the optic bulb. Unlike the remaining 
special sense-organs, the eye is not included within the skull-wall. 
The two portions are united both medially and laterally, the lateral . 
connection being established by the zygomatic arch (arcus 
zygomaticus), which bridges the lateral portion of the orbit. The 
facial portion has also a somewhat conical shape, its apex being 
formed by the anterior extremity of the upper jaw and the incisor 
teeth. Its base is formed in part by the connection with the cranial 
portion, as already described, and also by the anterior walls of the 
orbits. 
The cranial portion exhibits an extensive posterior, nuchal 
surface (planum nuchale), situated in general at right angles to the 
cervical portion of the vertebral column and also to the dorsal, 
lateral, and ventral walls of the skull. This surface includes the 
external surface of the occipital bone, with the exception, chiefly, 
of the basilar portion of the latter. Its dorsal portion forms an 
area of attachment for the spinal and special occipital musculature. 
Its ventral portion is perforated by a large aperture, the foramen 
magnum occipitale, for the passage of the central nervous system 
from the cranial cavity into che vertebral canal. On either side 
of this is a smooth, ridge-like projection, the occipital condyle 
(condylus occipitalis), for articulation with the superior articular 
pitsof the atlas. Ata little distance lateral to the occipital condyle, 
the nuchal surface is continued downward through the medium of a 
somewhat triangular, pointed jugular or paramastoid process 
(processus jugularis). This structure is separated from the occi- 
pital condyle by a pronounced notch, the posterior boundary of a 
deep narrow excavation, the jugular fossa (fossa jugularis), which 
lies between the condyle and the tympanic bulla. The jugular 
process serves for the attachment of muscles belonging to the 
tongue, hyoid, and mandible, namely, the styloglossus, stylohyoidei 

