1872.] MR. A. SANDERS ON LIOLEPIS BELLI. 175 



Flexor femoris (figs. 12 & 13) is situated behind and somewhat 

 dorsad of the last ; it arises from the same fibrous raphe, covering 

 the flexor profundus femoris ; none of the fibres are derived from the 

 bone : passing in front of the pubis this muscle is inserted into the 

 surface of the femur in front of the vastus externus, in close proximity 

 to the head of the bone. 



Flexor profundus femoris (fig. 13) is a flat and thin layer of muscle 

 covering the anterior part of the dorsal surface of the pubis beneath 

 the flexor femoris ; the muscles of the two sides are continuous across 

 the middle line ; the anterior edge arises from the anterior point of the 

 pubis ; but the posterior edge is free. At the point of crossing over 

 the front of the pubis there is a tendinous intersection which is at- 

 tached to the dorsal surface of the femur close to the head ; from 

 this intersection muscular fibres run outwards, to be inserted into the 

 femur for about one third of its length, between the insertion of the 

 pyriformis on one side and that of the flexor femoris and vastus 

 externus on the other. 



Obturator internus (fig. 13) arises from the central line of the 

 dorsal surface of the pubis, from the dorsal surface of the ischium, 

 and from the symphysis of the same ; it covers the posterior two- 

 thirds of the foramen ; the fibres converge, and, passing over the 

 smooth surface in front of that part of the ilium which goes to form 

 the acetabulum, are inserted into the side of the tendon which con- 

 nects the tendinous intersection of the flexor profundus femoris with 

 the dorsal surface of the femur as above mentioned. The tendon in 

 question has also an attachment to the aponeurosis between the 

 flexor tibialis, pelvo-tibialis, and iliacus externus ; so that these four 

 muscles all act together on the thigh, flexing it forward and slightly 

 towards either the dorsal or ventral surface, through three points of 

 attachment, viz. one on the dorsal surface close to the head, through 

 the obturator internu3 and the flexor profundus, another further 

 down the thigh and slightly more ventrad, through the flexor pro- 

 fundus, then, again, quite on the ventral aspect, through the flexor 

 tibialis and iliacus externus ; in addition through the flexor tibialis and 

 pelvo-tibialis there would be a slight power of flexing the leg ; this 

 arrangement seems to indicate great power and activity in using the 

 hind limbs. 



Gluteus medius (fig. 12) arises from the ilium behind and dorsad 

 of the ilio-femoral articulation, and in front of the origin of the biceps, 

 being covered by the gluteus maximus ; it is inserted into the posterior 

 surface of the femur between the insertion of the next muscle and 

 that of the vastus externus, commencing a short distance beyond 

 the head of the bone and occupying about one fourth of its length. 



Quadratus femoris (fig. 12) arises from the ilio-ischiatic ligament, 

 behind the origin of the biceps ; it passes outwards and towards the 

 ventral surface, and is inserted into the posterior border of the tro- 

 chanteric ridge of the femur; it is firmly attached to the inner 

 border of the tendon of the pyriformis, which completely covers its 

 insertion. 



Vastus externus (fig. 13) occupies the outer and dorsal aspect 



