length of the spine.

With statistics and anatomic description, the extensor and flexor thigh muscles in francois leaf monkey were studied. Using stepwise regression, the origins and insertions' of the muscles, showing significant correlationship with the femur (E), are only the distance from the most anterior point of origin of the m. sartorius to the acetabular fossa (A) (r=0.68, t=3.33, P

M. mulatta, M. thibetana and M. assamensis have a part of sympatry in distribution areas and closed relationships in phylogeny, but there also exist certain differences among them in the morphology and function of skeleton. In recent years, on their locomotion and adaptive behaviors, the different viewpoints were suggested by many authors. The comparison of distal articular surface of humerus in these species were carried out in this paper. The major results based on 24 humerus including 48 sides are as follows:1. The results of the discriminant analysis suggest that the features and structures of humeral distal articulation of M. thibetana is similar to that of M. assamensis than that of M. mulatta.2. The relative width of articulation (AFT), olecranon fossa (OFW) and internal epicondyle (MEW), and the relative length of trochlea (THL) play more important rule to distinguish the three species of macaques. The. first discriminate function is: F1=13.64MEW-15.57ATF+23.500FW+14.09THL-9.63.3. The characters on distal articulation of humerus of the three species of monkeys differ evidently from the apes.4. The results of principal component analysis show that the locomotion of M. mulatta is similar to Presbytes obscurus, Hylobates and M. nemestrina, and it seems that they are more adaptive to arboreal movement than that in M. thibetana and M. assamensis based on the osteological features and functional morphology of the distal articular surface of humerus.