xi SKULL 495 



inner and anterior region of each is given off, op- 

 posite the third cheek-tooth, a horizontal, inwardly 

 directed process (pafi\ which, articulating in the middle 

 line with its fellow of the opposite side and in front 

 with the palatine process of the maxilla, forms the pos- 

 terior part of the bony support of the hard palate. The 

 bones usually known as pterygoids are small irregular 

 plates attached to the posterior edge of the correspond- 

 ing palatine and the > pterygoid process of the alisphenoid ; 

 each ends ventrally in a backwardly-curved process. 



The squamosals* (sq) are a pair of plates which overlap 

 and complete the side-walls of the brain-case (p. 491) in 

 front of the periotics : they articulate with the frontals, 

 parietals, orbitosphenoids, and alisphenoids. From the 

 outer face of each is given off a strong zygomatic process, 

 which bears on its under surface the articular facet for 

 the lower jaw, and further back a slender process 

 (p.t.sq) arises which . is applied to the outer surface 

 of the periotic. 



The zygomatic processes of the squamosal and maxilla 

 respectively are united by a flat bar of bone, thejugal* (ju\ 

 which in the adult is fused with the latter. All these 

 three bones therefore take part in forming the zygomatic 

 arch. 



Most of the apertures for the transmission of the cerebral nerves have 

 so far not been mentioned : the branches of the olfactory nerve, as we 

 have seen, pass out through the numerous apertures in the cribriform 

 plate (Fig. 133, etk], and the optic foramen (opt. fo, II) is situated 

 between the orbitosphenoid and presphenoid. Behind and below the 

 optic foramen is a vertical aperture the sphenoidal fissure (sph. /) 

 between the basisphenoid and alisphenoid, which transmits the third, 

 fourth, and sixth nerves, as well as the ophthalmic and maxillary divisions 

 of the fifth. Between the periotic and alisphenoid is a large space 

 (Vmn), through the anterior part of which the mandibular division of 



