THE SKQLL. 305 



narial passage, whicli they separate from the 

 orbits. In front they are produced inwards 

 into the horizontal palatal processes, which 

 meet each other in the median plane in the 

 roof of the mouth, opposite the grinding teeth, 

 forming the posterior third of the bridge of 

 bone supporting the hard palate. 



lii. The maxilla are a pair of large irregular bones 

 forming a large part of the skeleton of the 

 upper jaw and of the face. 



The body, or alveolar portion, of each 

 maxilla projects into the front part of the orbit, 

 and is excavated by the alveoli or sockets for 

 the grinding teeth. Its inner surface is covered 

 by the palatine behind ; and in front is pro- 

 duced inwards into the horizontal palatal 

 process, which meets its fellow in the median 

 plane, and forms the anterior part of the bony 

 bridge supporting the hard palate. 



From the outer side of the body arises the 

 stout zygomatic process, which is prolonged 

 upwards into the orbital process, forming the 

 anterior boundary of the orbit. In front, the 

 maxilla is prolonged into the large fenestrated 

 facial plate, which forms the lateral boun- 

 dary of the olfactory chamber, and is per- 

 forated just above the first grinding tooth by 

 the infra-orbital foramen, for the passage of 

 the maxillary division of the trigeminal nerve. 



iv. The premaxillcB are a pair of bones forming the 

 anterior part of the upper jaw, and lodging the 

 incisor teeth : they articulate with the maxillse 

 behind, and with each other in the median 

 plane in front. 



The upper and posterior angle of each 

 premaxilla is produced backwards into a 

 long nasal process, which lies along the outer 



