178 



MAMMALIAN ANATOMY 



The superior border is the longest ; it is straight, slightly serrated, 

 and is united to the corresponding border of the opposite parietal by 

 the sagittal suture. 



The posterior-superior angle is cut off obliquely and becomes that 

 curved upper part of the posterior border which articulates with the 

 inter parietal. 



The posterior border is arcuate ; it is bevelled at the expense of 

 the inner surface, especially above, and overlaps the interparietal and 

 occipital bones. Near its upper end is a large foramen for a venous 

 sinus. Its lower end terminates in the posterior-inferior angle, which 

 is more or less prominent. 



The inner surface (Fig. 117) is deeply concave, and is marked by 



FIG. 117. 



Tentorium. 



With Opposite Parietal. 



With Interparietal. 



With Occipital. 



free Edge of Tentorium. 



Fossa for Petrous of Temporal: 



With Frontal. 



Groove for Artery. 

 Alisphenoid. 



With Temporal. 



With the part of the 

 Tentorium formed 

 by the Aiispheiioid. 



LEFT PARIETAL, INNER SURFACE. 



three longitudinal and three vertical wide grooves, which fit over the 

 convolutions of the middle lobe of the brain. The upper longitu- 

 dinal groove runs the length of the bone and ends posteriorly in the 

 upper part of the interval between the base of the tentorium and the 

 back part of this surface. The middle longitudinal groove does not 

 run so far back, but ends by turning downward to join the posterior 

 and larger vertical groove. The lower groove is joined in front and 

 behind by the upper ends of the anterior and middle vertical grooves, 

 which are continued down on the inner surface of the squamous of the 



