58 OSTEOLOGY. 



foramen incisivuin for the passage of the palato-labial artery ; 

 and an inferior, which is smooth, slightly concave, and marked 

 by a continuation of the palatine groove, which terminates in the 

 foramen incisivum. Between the external and inferior surfaces 

 is a very thick curved border, containing anteriorly three alveoli 

 for the incisor teeth, behind which is a sharp portion, which helps 

 to form the interdental space. At the posterior part of the 

 border, in the male animal, there is a cavity which, with that on 

 the anterior extremity of the superior maxilla, forms the alveolus 

 for the canine tooth. 



The processes are- external and internal. The external, the 

 largest and longest, is continuous with the base, and flattened 

 from side to side. Its outer surface is convex and smooth, its 

 inner rounded above, and covered by the mucous membrane of 

 the nasal chamber ; inferiorly, it is roughened to articulate with 

 the superior maxilla ; its posterior extremity is thin, and attached 

 between the superior maxilla and the nasal bone. The internal 

 or palatine process is a thin flexible plate, which joins its fellow 

 internally by a dentated suture ; their superior surface forms part 

 of the floor of the nasal fossae, and their inferior part, which is 

 smooth, forms part of the bony palate. 



The premaxillge are joined by fibro-cartilage in the young 

 animal and by ossification in the old, the junction forming the 

 symjyhysis ; they articulate with each other and with the superior 

 maxilla, nasal bone, and vomer. 



MALAR BONE. 



(Fig. 12. 7.) 



The Malar, Zygomatic, or Jugal bone, situated at the antero- 

 inferior part of the orbital fossa, is irregularly triangular in shape, 

 with a broad anterior part, ending in a sharpened posterior point. 

 It presents for consideration three surfaces, a base, and the 

 zygomatic pi'ocess. 



The external or facial surface is smooth, somewhat convex, 

 and has, inferiorly, a sharp ridge, the zygomatic ridge, continued 

 posteriorly by the zygomatic process, which meets the process of 

 the same name of. the squamosal bone, the two forming the 

 zygomatic arch. The internal or maxillary surface is irregularly 

 concave, the posterior part helping to enclose the maxillary sinus. 

 The superior or orbital surface is concave, and forms the antero- 



