46 PALATE BONKS. 



smooth and convex, and pierced by several small openings which give 

 passage to filaments of the temporo-malar nerve and minute arteries. 

 The internal surface is concave, partly smooth and partly rough ; 

 smooth where it forms part of the temporal fossa, and rough where it 

 articulates with the superior maxillary bone. 



The frontal process ascends perpendicularly to form the outer 

 border of the orbit, and to articulate with the external angular process 

 of the frontal bone. The orbital process is a thick plate, which projects 

 inwards from the frontal process, and unites with the great ala of the 

 sphenoid to constitute the outer wall of the orbit. It is pierced by 

 several small foramina for the passage of temporo-malar filaments of 

 the superior maxillary nerve. The maxillary process is broad, and 

 articulates with the superior maxillary bone. The zygomaiic process, 

 narrower than the rest, projects backwards to unite with the zygoma 

 of the temporal bone. 



Development. By a single centre ; rarely by two or three. In 

 many animals the malar bone is permanently divided into two por- 

 tions, orbital and malar. Ossification commences in the malar bone 

 soon after the vertebrae. 



Articulations. With four bones ; three of the cranium, frontal, 

 temporal, and sphenoid ; and one of the face, the superior maxillary 

 bone. 



Attachment of Muscles. To five ; levator labii superioris proprius, 

 zygomaticus minor and major, masseter, and temporal. 



PALATE BONES. The palate bones 

 are situated at the posterior part of 

 the nares, where they enter into the 

 formation of the palate, the side of 

 the nose, and the posterior part of the 

 floor of the orbit ; hence they might 

 with great propriety be named the pa- 

 lato-naso-orbital bones. Each bone re- 

 sembles in general form the letter L, 

 and is divisible into a horizontal plate, 

 a perpendicular plate, and a pterygoid 

 process or tuberosity. 



The horizontal plate is quadrilateral ; 

 and presents two surfaces, one superior, 

 which enters into the formation of the 

 floor of the nares, the other inferior, 

 forming the posterior part of the hard palate. The superior surface 



* A posterior view of the right palate bone in its natural position; it is 

 slightly turned to one side to obtain a sight of the internal surface of the per- 

 pendicular plate (2). 1. The horizontal plate of the bone; its upper or nasal 

 surface. 2. The perpendicular plate ; its internal or nasal surface. 3, 10, 11. 

 The pterygoid process or tuberosity. 4. The thick internal border of the hori- 

 zontal plate, which, articulating with the similar border of the opposite bone, 



