50 
THE DOGS SKULL. 
most posterior the cerebellar fossa, extending 
as far as the periotic bone and the junction of 
the supra-occipital and parietal, it lodges the 
cerebellum; anterior to this is the cerebral 
fossa, lodging the cerebrum. On the posterior 
portion of the orbito-sphenoid and frontal is 
a slight ridge, which forms an imperfect division, 
and lodges the frontal and temporal lobes of 
the brain respectively. 
In the oceipital segment notice the basi-occipital 
The 
The 
forming the inferior margin of the foramen 
magnum, and its suture with the ex-occipital; 
above the ex-occipital is a larger cancellous 
bone, the supra-occipital, dorsal to which, and 
between the two parietals, is a long narrow 
bone, the inter-parietal. 
parietal segment consists of the basi-sphenoid 
below, in which notice in the middle, on the 
the sella turcica 
—which lodges the pituitary body. The basi- 
inner surface, a little hollow 
sphenoid is bounded on either side by a wing- 
like bone, the ali-sphenoid, dorsal to which are 
the large parietals. Notice that between the 
occipital and parietal segments there are a 
series of bones—the periotic and squamosal— 
which unite the two segments inferiorly. 
basal portion of the frontal segment is formed 
by the pre-sphenoid, from the sides of which 
project the orbito-sphenoids ; above these the 
frontals are situated, forming the dorsal, and 
