The Vascular System 223 



At the point of union of the branches cm^ and 

 z" a sort of simple plexus may be formed from which 

 two vessels, n, pass to the posterior nasal region, 

 and two vessels pass forward along the side of the 

 upper jaw. Of the latter two vessels one, which 

 may be called the inferior dental of the maxilla, dm, 

 is very small and extends along the maxilla to its 

 very tip, at the base of the teeth and ventral to the 

 palatine bone ; the other, which is larger and may be 

 called the superior dental of the maxilla, dm^, 

 extends cephalad along the mesial side of the 

 maxilla, dorsal to the palatine bone; it sends nu- 

 merous twigs into the maxillary bone among the 

 roots of the teeth. After passing nearly to the 

 end of the snout, the superior dental, dm \ suddenly 

 forms a loop towards the median line and passes 

 as a straight branch, n', directly caudad, near 

 and parallel to the median plane. The branch n^ 

 extends along the floor of the nasal cavity and, 

 after giving off twigs to this chamber, ends in a 

 network of vessels, o^, on the anterior surface of 

 the eyeball and socket. 



A pair of very small arteries, n% may be seen in 

 the nasal chamber between and parallel to the 

 branches, n' ; they lie close to each side of the nasal 

 septum and supply the anterior nasal region. 

 They apparently arise, as shown by the broken 

 lines, from the loop of the superior dental 

 artery, dm', though this could not be definitely 

 determined. 



