THE SKELETON. 3 1 



auditory meatus, which gives passage to the auditory nerve. 

 Close examination reveals a division of the canal into two 

 parts, a ventral for the eighth nerve and a dorsal, the aque- 

 ductus Fallopii, for the facial nerve. This aqueduct twists 

 through the petrous laterad, and thence between the petrous, 

 squamosal, and mastoid to the stylomastoid foramen (Fig. 



17)- 



The parietal bone is paired and joins its fellow in the 

 median line, forming the caudal half of the sagittal suture. 

 Its point of greatest convexity is the parietal eminence. Its 

 cerebral or internal surface presents slight arborescent 

 grooves which in the recent state sheltered the meningeal 

 artery of the brain. The plate of bone projecting obliquely 

 craniad from the caudal border of the parietal is the tento- 

 riuni, an ossification of the dura mater separating the cere- 

 brum from the cerebellum. 



The interparietal is a triangular bone situated at the 

 junction of the two parietals and occipital bones. Its 

 sutures are usually obliterated quite early. 



The occipital (Figs. 16, 17, and 18) is a single bone 

 surrounding the foramen magnum and articulating with 

 the interparietal, parietals, temporals, and sphenoid. In the 

 young kitten it is composed of four parts : the supraocci- 

 pital, lying dorsal to the foramen magnum, the two exocci- 

 pitals, lying laterad of it, and a basioccipital, bounding it 

 ventrally. The crescentic elevation on the supraoccipital 

 near its parietal margin is the lanibdoidal ridge, to which 

 several muscles are attached. 



The exoccipitals bound the cerebellum laterally and sup- 

 port the occipital condyles, which articulate with the atlas 

 or first vertebra. Immediately caudad of the bulla is the 

 par occipital process. There are two foramina, one of 

 which, the anterior condyloid, opens ventrally with the jug- 

 ular foramen adjacent to the bulla, while the other, the 



