The Gluteal and Femoral Muscles in a Marmoset. 193 



4. A branch which ran downwards superficial to the 

 gemelli, and having supplied a branch to each gemellus, 

 ended in the caudo-femoralis near its origin. 



5. A large branch (given off from that part of the nerve 

 which became the internal popliteal) which ran down over 

 the gemelli and quadratus and internal to caudo-femoralis, 

 between that muscle and semi-tendinosus. It supplied 

 branches to caudo-femoralis, biceps, semi-tendinosus, semi- 

 membranosus, and presemi-membranosus. 



While the natural division of the great sciatic into the 

 two popliteal nerves was at the middle of the thigh, the 

 two popliteals were separated without difficulty as far up as 

 their origin from spinal nerves. The external popliteal was 

 formed mainly from the 5th lumbar, a few fibres came from the 

 small communicating branch from the 4th, and the rest from 

 the 6th. The internal popliteal was formed chiefly from the 

 6th lumbar, and the communicating branch of the 4th, the 

 6th, and the 1st sacral each contributed a few fibres. 



The other branches of the great sciatic were also traced 

 ' back to their origin from spinal nerves. The branch to the 

 hamstrings got fibres equally from the 5th and 6th lumbar, 

 and a few from the 4th lumbar. 



The branch to quadratus femoris came from the 5th lumbar. 



The branches to the gemelli and caudo-femoralis, and to 

 'the obturator internus, both came from the 4th and 5th 

 lumbar nerves. 



The branch to the upper division of gluteus maximus 

 came from the 6th lumbar and 1st sacral ; that to the lower 

 part came from the 1st, and was joined by a branch from the 

 2nd sacral. 



The branches of the superior gluteal nerve were also traced 

 back to their origin. The supply to the gluteus medius came 

 exclusively from the 6th lumbar nerve. The supply to the 

 two middle pieces of gluteus minimus came from tlie 5th 

 and 6th The supply to the other two parts came from the 

 5th only. The supply to the superior part of tensor came 

 from the 6th, while that to the lower came from the 5th. 



The nerve to pynformis had two roots, one from the 6 th 

 lumbar and one from the 1st sacral nerve. 



