THE VASCULAR SYSTEM 203 



Botalli In the Salamander, it seems not improbable that the A. cutanea 

 magna of the Frog may be the morphological equivalent of the 

 ductus Botalli+the A. pharyngea ascendens of Salamandra. The 

 differences in detail between the branches of the A. pharyngea ascen- 

 dens and those of the R. auricularis may easily be accounted for 

 by the difference in the structure of the auditory organ in the two 

 animals. 



C. The -palato-n a sal artery (PI. XIX, fig. 70) (a.pal.nas.) is, in the 

 Salamander, a branch of the systemic arch. It arises dorsally close to 

 the middle line, in the region of the occiput, and either close to, or 

 jointly with the vertebral artery. Almost immediately it gives off a 

 small twig to the dorsal wall of the pharynx, and then bends round 

 laterally, following the curve of the systemic arch as far as the palatine 

 foramen, when it turns sharply round mesially to the inner border 

 of the orbit. At this bend four branches arise. 



(i) RR. pharyngei^ forming a rich network over the dorso-lateral 

 pharyngeal wall. Usually two in number. 



(ii) R. -pterygoideus (a.pt.), a small branch passing along the ptery- 

 goid process of the palato-pterygoid and shortly after, at a point ven- 

 tral to the origin of the M. retractor bulbi a maxillo-palatine artery 

 is given off. 



(iii) A. maxillo-palatina (a.max.pal.), arising laterally and running 

 in company with the maxillary vein. It is distributed to the roof 

 of the mouth underlying the postero-lateral corner of the orbit and 

 then turns anteriorly and is continued a short distance along the 

 posterior region of the maxilla. 



(iv) The posterior palatine artery, arising mesially and ramifying 

 over the whole of the posterior region of the palate. 



At the inner posterior angle of the orbit the palato-nasal artery 

 turns anteriorly and gives off the anterior palatine artery and then 

 continues forward as the orbito-nasal artery. 



(v) The anterior palatine artery (a. pal. a.) also turns anteriorly 

 and runs alongside the palatine vein and nerve supplying the mucous 

 membrane of the middle and anterior regions of the roof of the 

 mouth. The rich vascular network around the vomero-palatine teeth 

 is also supplied by this artery. 



(vi) The orbito-nasal 2iYte.Yy must not be confused with the orbito- 

 nasal of the Frog, which runs dorsal to the eye-muscles. It passes 

 obliquely in an antero-dorsal direction across the surface of the orbito- 

 sphenoid to the dorsal side of the inner anterior angle of the orbit, 

 where it gives off a small twig, viz. : 



