xi SKULL 495 



anterior region of each is given off, opposite the third 

 cheek-tooth, a horizontal, inwardly directed process 

 (pal 1 }, 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 posterior 

 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 corre- 

 sponding 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 over- 

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

 in front of the periotics : they articulate with the f rentals, 

 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, the jugal* 

 (jii), 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, eth, I), 

 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 

 ( s pj lm f) 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 (V mn), through 

 the anterior part of which the mandibular division of the 



