palate, since by its anterior margin it articulates with both 

 maxilla [7] and palate bone [8] (5 figure 47). 



The Quadrato-JUGAL (Os qwiil I'd I o-jntjalc) [Fig. 20] a 

 flat plate of bone of irregular crescentic outline, presents 

 margins for articulation with jugal [1], postfrontal [2], 

 squamosal [3] and quadrate bones, and also a margin [7] 

 forming a large portion of the boundary of the zygomatic 

 sinus. The margin of articulation with the quadrate is 

 arcuate above (margo tympanicus) [4] where it bounds the 

 tympanic fossa in that bone, and below this is straight 

 (margo suspcnsoria) [5] articulating with the suspensory 

 ramus of the quadrate. At the junction of the two seg- 

 ments, is a prominent sharp infra t .ympanie spine [6]. 



The Squamosal (Os squamosale) [Fig. 21] though a flat 

 bone, is particularly stout and quite belies its name, of 

 irregular shape it presents two surfaces and six borders. 

 The postero inferior border [1] forms the outer lip of a 

 sulcus which lodges the outer head of the squamoso- 

 maxillaris muscle (sulcii* sqiKiumso-maxillavis lateralis) 2]. 

 Above this border the temporal margin [4] makes, in the 

 articulated skull, a slight angle with the temporal margin 

 of the parietal, and like it forms the posterior margin of 

 the roof of the temporal fossa. The superior margin [5] 

 articulates with the parietal, in front of this margin is 

 that [6] for articulation with the post frontal, and making 

 a sharp angle with this last is a short quadrato- jugal margin 

 [7]. The bone also articulates with the parotic ramus of 

 the quadrate by a deeply concave margin (margo tympani- 

 cus) [8] bounding the tympanic fossa behind, and a fairly 

 extensive area (fades quadrata) [9] on the inferior surface 

 of the parotic process. This last (processus pavoticus) [70 

 fig. 43] is a three sided pyramidal mass attached to the 

 inner side of the bone in the postero-inferior region. The 

 process is evenly rounded above, beneath it articulates with 



