2i8 THE SALAMANDER 



and nerve. One noteworthy branch Is the R. recurrens which runs 

 back around the proximal end of the fibula close to the N. peroneus 

 and anastomoses with the distal extremity of the gluteal artery. ^ 



The A. interossea proper passes right down the leg without 

 branching, and, at the distal border of the M. interosseus, passes to 

 the ventral side of the tarsus, and then, as the A. perforans tarsi 

 (Manno) (A. perforans inferior, Osawa), penetrates to the dorsal 

 side of the foot through the foramen between the tibiale and inter- 

 medium. Here it is known as the A. dorsalis pedis and divides into 

 four branches, each of which divides again to form the AA. digitales 

 supplying the adjoining sides of the toes. 



6. Branches of the Pulmonary Arch (PI. XXIII, fig. 77). 



The ventral oesophageal (or pharyngeal) artery (a.oes.v.) arises 

 mesially from the pulmonary arch at the posterior border of, and 

 ventral to, the dilatator laryngis muscle. It passes anteriorly, dorsal 

 to the M. cephalo-dorso-subpharyngeus and ramifies over the whole 

 ventral surface of the pharynx and the floor of the mouth as far as 

 the root of the tongue. Its most posterior branch is the laryngeal 

 artery supplying the muscles of the larynx. 



The dorsal oesophageal {or pharyngeal) artery (a.oes.d.) arises later- 

 ally from the pulmonary immediately opposite the ventral vessel, and 

 bends dorsally round the oesophagus to meet a similar vessel from 

 the opposite side, with which it fuses, and then continues as a median 

 artery for some distance down the oesophagus posteriorly. These 

 arteries thus form a Y-shaped vessel from which branches ramify- 

 over the whole of the dorsal surface of the oesophagus and pharynx. 



The pulmonary artery (a.pul.), as the continuation of the arch may 

 now be called, passes posteriorly, rather closely embedded in connec- 

 tive tissue, and enters the lung on its dorso-lateral border about a 

 quarter of the way down. It commences to divide just before its entry 

 into the lung. 



Unless the small cutaneous branches of the ductus Botalli may be 

 taken to correspond with the cutaneous artery of the Frog, this vessel 

 is not represented in the Salamander (cf. pp. 202—3). 



7. The Venous System. 



The Venous Trunks (PI. XV). 



To be logical the course of the veins should be traced from their 

 distal origins towards the heart, but, since it is impossible to see the 



'^ The A. interossea externa may separate from the A. ischiadica before the AA. 

 interossea and plantaris, the actual order of branching being somewhat indefinite. 



