138 THE SKULL [CHAP. 



vertical ridge formed by the pterygoid, the pterygoid process 

 of the alisphenoid and the palatine bones, and continuing the 

 outer wall of the narial passage backwards beyond the bony 

 palate. The palatine bone forms a considerable part of 

 the inner wall of the orbit, joining the frontal anteriorly 

 though separated from it for a considerable space posteriorly 

 by the orbitosphenoid. The lacrymal (Z) appears in the 

 anterior boundary of the orbit, the malar (Ma) joins its outer 

 boundary, and the upper surface of the hinder end of the 

 alveolar border of the maxilla projects backwards, so as to 

 form a partial floor to its anterior extremity. In front of 

 the orbits the face is formed above by the long narrow nasals 

 (Na) pointed behind, and widening and obliquely truncated 

 in front to form the upper border of the narial aperture ; on 

 each side by the maxillae (Mx) having near the middle of 

 their surface the large infraorbital foramen (id), through 

 which the 'terminal branches of the second division of the 

 fifth or sensory nerve of the face pass to be distributed to the 

 upper lips and whiskers ; and quite anteriorly by the pre- 

 maxillae (PMx\ which complete the boundaries of the nares, 

 and send up narrow processes between the nasals and 

 maxillae towards, though not meeting with, similar processes 

 which run from the frontals. 



The inferior surface of the skull (Fig. 47) is formed an- 

 teriorly by the nearly flat, elongated surface of the palate, 

 narrower in front than behind, composed anteriorly of the 

 premaxillse (PMx) ; then of the maxillae (Mx), which diverge 

 posteriorly and allow the palatines (PI) which form the 

 hinder border to reach in the middle line almost to the 

 centre of the palatal surface. In front and at the sides this 

 surface is bounded by the alveolar borders of the premaxillse 

 and maxillae in which the teeth are set. Anteriorly are two 

 considerable oval foramina (apf\ placed longitudinally very 



