334 



MAMMALIAN ANATOMY 



plate in the cat, but are elevated on a high nasal plate the inner 

 surface of which is crossed by a backward extension of the crest for 

 the maxillo-turbinal. In the cat this crest fades away behind on the 

 posterior part of the nasal surface of the maxillary bone. 



The posterior border of this nasal plate (Fig. 261), the lower part 

 of the posterior border of the entire bone, is prolonged downward and 



FIG. 261. 



FIG. 262. 



RIGHT PALATINE BONE. POSTERIOR VIEW. 



1, palatine plate; 2, nasal plate; 3, pyramidal pro- 

 cess ; 4, articular border for the left palatine bone ; 

 5, posterior nasal spine ; 6, turbinal crest ; 7, spheno- 

 palatine notch, between 8, the ethnioidal, and 9, the 

 sphenoidal process; 10, groove for the internal ptery- 

 goid plate of the sphenoid bone; 11, position of the 

 posterior palatine canal. 



RIGHT PALATINE BONE. EXTERIOR VIEW. 



1, rough surface articulating with the maxillary and 

 diminishing the aperture of the antrum ; 2, posterior 

 palatine canal, completed by the maxillary ; 3, spheno- 

 palatine notch ; 4, 5. 6, ethmoidal process ; 4, surface 

 directed towards the spheno-maxillary fossa ; 5, orbital 

 surface; 6, maxillary border; 7, sphenoidal process; 

 8, pyramidal process. 



outward into the pyramidal process, or tuberosity. It presents a 

 rough external area for the external pterygoid plate of the sphenoid ; 

 a smooth middle groove, which, coming between the two pterygoid 

 plates, forms part of the anterior Avail of the external pterygoid fossa 

 (Fig. 258), and an internal groove, which receives the internal pterygoid 

 plate. 



In a notch between this groove and the edge of the horizontal plate 

 are the openings of the accessory posterior palatine canals. The 

 posterior border of the nasal plate is continued upward to the poste- 

 rior border of the small sphenoidal process, and articulates with the 

 internal pterygoid plate. 



On the external surface of the nasal plate (Fig. 262) the outer 

 side of the pyramidal process and the lower border are rough and 

 join the tuberosity of the maxillary ; they correspond to the surface 

 and border on the hook-like extension of the maxillary process in the 

 cat. In front of the rough triangular area on the tuberosity is a deep 

 groove or canal, the posterior palatine canal, which is continued 

 upward to the external surface of the sphenoidal process as the smooth 

 inner wall of the pterygo-maxillary fissure. In front of the groove 



