710 ME. F. G. PAUSONS ON THE [Juue 16, 



by Paterson as derived from the dorsal divisions of the plexus, 

 the median as derived from the ventral. In all the animals 

 dissected by Paterson, and in all that I have hitherto dissected, 

 the radial nerve came from the musculo-spiral ; in this case, 

 however, the radial rose on both sides from the median, although 

 no connection between that nerve and the dorsal roots was observed 

 in the plexus. 



The arrangement of the Lumbar Plexus of the Rocls-Kangaroo 

 closely resembles that of tlie Uuscus described by Cunningham ' ; 

 it is iformed by the 2nd, 3rd, 4th, and a large part of the 6th 

 lumbar nerves, the 1st lumbar being distributed to the abdominal 

 walls. 



The genito-crural nerve is very small and rises from the 2nd 

 and 3rd lumbar, whence it runs down to supply the cremaster, no 

 cTural branch being seen. 



The anterior crural comes from the 3rd, 4th, and 5th lumbars, 

 and emerges from the outer sui'face of the psoas, soon after which 

 it gives off the external cutaneous to supply the skin of the outer 

 ■ side of the thigh. As soon as the nerve has passed under 

 Poupart's ligament it gives off a cutaneous branch to the sldn of 

 the front and inner side of the thigh. Soon after this a branch 

 runs outwards to supply the sartorius, and from this a twig enters 

 the superficial surface of the rectus femoris. The next branch is 

 the long saphenous which comes off from the inner side of the 

 nerve, passes superficial to the external circumflex artery, and 

 supplies the skin on the inner side of tlie leg below the knee. 

 The rest of the branches of the anterior crural pass deep to the 

 external circumflex artery and supply the quadriceps extensor set 

 of muscles. The obturator nerve comes from the anterior divisions 

 of the 4th and 5th lumbar, passes to the obturator foramen, and 

 divides into a brush of branches which supply the adductor 

 muscles as well as the gracilis. No distinct division into super- 

 ficial and deep parts was noticed. 



In the plexus, branches to the psoas come from the 2nd and 

 3rd as well as the junction between the 4th and 5th lumbar 

 nerves. 



The Sacral Plextis is formed by the 5th and 6th lumbar and the 

 greater part of the first sacral nerves, which all unite to form the 

 main trunk of the great sciatic. Prom the junction of the 5th 

 and 6th lumbar nerves the superior gluteal is given off, as is tlie 

 casein the sacral plexus of the Cusms; this nerve supplies the 

 gluteus medius, minimus, and quartus. The inferior gluteal 

 comes off in common with the small sciatic alter the union of the 

 1st sacral with the cord formed by the 5th and 6th lumbar (lumbo- 

 sacral cord) ; it supplies the gluteus maximus and the anterior part 

 of the biceps. The small sciatic supplies the skin of the back of 

 the thigh as usual. 



The pudic nerve is formed by the part of the 1st sacral which 



' Journ. Anat. vol. xv. p. 265. 



