188 Proceedings of the Royal Physical Society. 



Among monkeys generally, an insertion in common with 

 gracilis is frequently met with. 



Eectus femoris arose by two heads, a straight and a 

 reflected as in man, but there was less of a break in the 

 continuity between them. The straight head arose from the 

 anterior inferior iliac spine and the bone immediately external 

 to that. The reflected was a flattened tendon attached to 

 the ilium above the acetabulum. This head could be traced 

 as a flattened tendon almost to the insertion of the muscle. 

 It lay imbedded in the substance of the muscle, with its 

 surfaces directed outwards and inwards, its edges backwards 

 and forwards. It tapered to a point inferiorly. It was 

 surrounded by muscle except the upper part of the posterior 

 edge, which was free. Muscle fibres took origin from both 

 sides of it. The tendon of insertion of rectus was attached 

 to the upper border or end of the patella, and some fibres 

 are continued over the anterior surface of the patella to the 

 ligamentum patellae. 



The other three heads of the quadriceps extensor were 

 relatively not so powerful as in man. The two vasti had 

 very limited origins, the attachments to the back of the 

 femur and inter-muscular septa being altogether wanting, 

 and these two muscles did not form the large muscle masses 

 they do in man, but were somewhat fusiform in shape, and 

 they were very much more easily separated from the crureus 

 than they are in man. 



Vastus externus arose from a depression on the anterior 

 and outer aspects of the great trochanter below the insertion 

 of scansorius, and from a very small part of the bone below 

 in front of the upper part of the insertion of gluteus 

 maximus. A few fibres took origin from the front of the 

 capsule of the hip joint. It did not arise from the back 

 of the femur, or from the external inter-muscular septum. 



Vastus internus was only about one-third the bulk of 

 vastus externus, but it had a broader origin. It was attached 

 to the antero-internal surface of the shaft of the femur 

 immediately below the line joining the trochanters in front. 

 This attachment occupied about a sixth of the length of the 

 femur. It extended outwards and upwards to the origin of 



