204 THE SALAMANDER 



(a) R. descendens which passes vertically downwards and spreads 

 over the palate in that region. 



The orbito-nasal artery then passes through a foramen in the pro- 

 cessus antorbitalis, and divides into two terminal branches. 



{}}) A mesial nasal artery which immediately divides again into 

 dorsal and ventral rami which bifurcate and spread around the 

 mesial border of the nasal capsule. 



{c) A posterior nasal artery (a.na.p.) which passes round the orbital 

 border of the nasal capsule. Soon after its origin it gives off four 

 twigs as under. 



(i) The anterior orbital artery which passes backwards out of the 

 same foramen as that by which the main artery (i.e. the orbito-nasal) 

 entered. It is distributed to the pre-orbital glands of that region and 

 also sends a branch to the overlying skin, and another which anasto- 

 moses with the dorsal branch of the ophthalmic artery, that is, with 

 a branch of the internal carotid (see p. 201). 



The posterior nasal artery then proceeds to the lateral border of 

 the nasal capsule where it divides into the remaining three twigs. 



(2) The lateral nasal artery (a.na.l.) which supplies the lateral 

 border of the nasal capsule. 



(3) The mesial fnaxillary artery (a.max.m.) which turns posteriorly 

 and supplies the middle region of the upper jaw. 



(4) The anterior maxillary artery (a. max. a.), turning anteriorly to 

 supply the upper jaw in the region of the snout. 



It will doubtless have been noticed that the vessel which has 

 just been described as the palato-nasal artery bears a strong re- 

 semblance to one described by Gaupp for the Frog, and called by 

 him the arteria occipitalis. Particularly is this so as regards its origin 

 and its nasal branches. This agreement was considered by Bethge to 

 be sufficiently close to justify his adopting the same name for the 

 vessel in the Salamander, viz. arteria occipitalis. The A. occipitalis 

 of the Frog, however, is a dorsal vessel, its orbito-nasal branch pass- 

 ing 'iiber den M. rectus oculi superior (Gaupp), while in this animal 

 also the palate is supplied by the palatine artery from the internal 

 carotid. In view of these facts a non-committal name based on its 

 distribution has been adopted here. 



D. Vertebral artery (a.vert.) {arteria vertebralis collateralis^ Bethge). 

 It arises from the systemic arch close to, or together with, the palato- 

 nasal artery just lateral to the occipital condyles, and, after running a 

 short distance caudalwards, turns sharply in towards the vertebral 

 column and then runs close alongside it posteriorly right down the 

 body. It commences at about the level of the first vertebra, and 



