THE FROG. 221 



a. The vastus intermix: the anterior division, 

 which has been already seen on the front of 

 the thigh. (2. d. rj.) 



/8. The vastus extemus : the posterior division ; it 

 arises from the hinder edge of the iliac bone. 



7. The rectus femoris anticus : the middle division 

 of the triceps ; it arises from the posterior part 

 of the ventral border of the iliac bone. For the 

 insertijon of the triceps femoris, see 2. d. r). 



The glutceus : this muscle arises from the hinder 

 two-thirds of the external surface of the ilium ; 

 it runs down between the vastus externus and 

 the rectus anticus to be inserted into the back of 

 the head of the femur. 



The fyxiformis. This arises from the posterior 

 part, of the urostyle and, passing inside the vastus 

 externus, is inserted into the shaft of the femur. 



The biceps femoris : a long thin muscle, lying 

 along the inner side of the vastus externus; it 

 arises from the iliac bone above the acetabu- 

 lum; below it divides into two pieces, one of 

 which is inserted into the middle of the shaft 

 of the femur, while the other ends in a rounded 

 tendon which is inserted into the back of the 

 distal end of the same bone. 



The serfiimemhranosus : a large muscle inside the 

 biceps; it arises from the upper posterior part 

 of the iliac symphysis and is inserted into the 

 aponeurosis round the knee-joint. 



Lying deep in the thigh, between the biceps 

 and semimembranosus muscles, will be seen the 

 femoral vessels and the sciatic nerve. 



