2i6 THE SALAMANDER 



ischio-femoralis and the ventral muscles of the tail — MM. caudall- 

 pubo-ischio-tibialis and caudali-femoralis. The other branch is the 

 lateral cloacal artery and is distributed to the gland, while a few twigs 

 go to the skin at the base of the tail. 



(d) The fourth and largest branch of the A. iliaca communis forms 

 the direct continuation of that vessel, and is the A. ischiadica^ or 

 sciatic artery (a. is.). It enters the limb posterior to the acetabulum, 

 and at first it is ventral to the corresponding vein, but within the 

 thigh it twists round to the dorsal side. 



(i) Its first branch is given off at about the middle of the thigh, and 

 corresponds in position and distribution with the y^.^ro///;z^^/<?;;2(9m 

 of the Frog, but it is a much smaller and less important vessel. 

 Only a small portion of it is distributed to the M. ischio-fiexorius, 

 the major portion passing to the skin on the postero-mesial aspect of 

 the thigh as the A. cutanea femoris posterior (Osawa) (A. cut. fem. 

 medialis, Gaupp). 



(ii) The most important branch of the A. ischiadica in the thigh is 

 the A. articularis genu tibialis (Osawa). This vessel passes to the 

 anterior aspect of the thigh round the ventral side of the distal end 

 of the femur, and comes to lie between the MM. pubo-ischio- 

 tibialis and pubo-ischio-femoralis. Here it breaks up into some four 

 or five branches which supply the muscles named and the MM. 

 pubo-tibialis and pubo-femoralis. Also there are one or two 

 cutaneous branches which doubtless represent the A. cutanea genu 

 medialis superior (Gaupp) of the Frog. Close to the origin of the 

 A. art. gen. tib. a small twig arises for the M. femoro-fibularis. Two 

 other branches are worthy of mention. The first of these is the R. 

 ascendens (Osawa), a recurrent branch which passes back up the 

 thigh and is distributed to the MM. pubo-ischio-femoralis internus 

 and externus. Whether the twigs of this ramus anastomose with 

 those of the A. femoralis is uncertain, but it is possible that they may. 

 The second branch is the R. descendens (Osawa). This passes over 

 the insertion of the M. pub. isch. tib. to the tibial side of the knee, and 

 continues down the leg in company with the N. saphenus to the pre- 

 axial side of the first digit. It supplies several cutaneous twigs to the 

 extensor side of the leg. 



(iii) Another branch arising from the A. ischiadica just proximal 

 to the foregoing is the A. articularis genu fibularis (Osawa). This 

 vessel leaves the sciatic artery postero-ventrally and supplies the pars 

 plantaris of the M. ischio-fiexorius and the insertion of the M. pub. 

 isch. tib. as well as the skin on the posterior aspect of the thigh 

 and knee. 



