ARTERIAL SYSTEM. 



183 



ing, give rise to the 

 pulmonary arteries, 

 a narrow ductus 

 Botalli, the lumen 

 of which is some- 

 times obliterated, 

 being usually re- 

 tained. Vessels for 

 the head and occi 

 pital region are of- 

 ten given off from 

 the roots of the 

 aorta. In the Ba- 

 trachians, which, in 

 consequence of the 

 union of the two 

 posterior branchial 

 arches, possess only 

 three vascular 

 arches, the aortic 

 root is the pro- 

 longation of the 

 middle arch on each 

 side, and gives off 

 the vessels of the 

 scapular region and 

 the anterior ex- 

 tremity, and often, 

 also, on one side an 

 artery to the viscera 

 (mesenteric artery). 

 The posterior arch 

 sends off the pul- 

 monary arteries and 

 a strong trunk to 

 the skin of the back, 

 but does not retain 

 its connection with 

 the roots of the 

 aorta. As in Fishes, 

 there is a renal-portal system, as well as an hepatic-portal system. 



Kl 



FI&. 625. a, Urinary and genital apparatus of the left Bide 

 from a male Salamander, partly diagrammatic. T, testes ; Ve, 

 vasa efferentia ; N, kidney with collecting urinary tubules ; 

 Mg, Mullerian duct ; Wg, Wolffian duct or vas def erens ; El> 

 cloaca; Dr, prostate glands, b, Urinary and genital ap- 

 paratus of the left side of a female Salamander without the 

 cloacal part. Ov, Ovary ; N, kidney ; HI, the urinary duct 

 corresponding to the Wolffian duct ; Mg, oviduct or Mul- 

 lerian duct. 



