This physiological fact agrees with the anatomical results of an extended study in the musculature of primates, especially of man, and Hartmann’s book on Anthropoid Apes supplies abundant evidence of the variations of the muscles of these animals, which are not at all more striking than their differing modes of life would suggest. It would be wearisome to quote all these, but a single muscle may be given as an example of a special ape’s muscle with variable distribution. It is called _latissimo-condyloideus_ and starts from the insertion of the _latissimus dorsi_ and passes along the inner aspect of the humerus for a variable distance. In the _baboon_ and others it goes to be inserted into the inner inter-muscular septum and the internal condyle of the humerus, in the _orang_ to the condyle, and in the _gibbon_ to the centre of the shaft. As to origin it proceeds from the insertion of the _latissimus dorsi_, but in the _gorilla_ from the coracoid process of the scapula and from two portions of the _pectoralis minor_, and is finally attached to the inter-muscular septum between the _brachialis anticus_ and the _triceps_; in the _chimpanzee_ it divides into an anterior and posterior portion, the former being attached to the inner condyle, the latter to the middle and inner head of the _triceps_; in the _orang_ it divides similarly, but in one particular example it had an anterior thin portion attached by a slender tendon to the coracoid process of the scapula and a posterior portion arose from the _latissimus dorsi_; in the _white-handed gibbon_ it arose from the function of tendons from the _latissimus dorsi_ and _teres major_ and was inserted into the fascia between the tendon of the _biceps_ and the _brachialis anticus_. Such a divergence as this within the strict limits of an anthropoid muscle, concerned in the various forms of climbing action of these apes, can only suggest an origin from a divergent set of functions and small details in their respective modes of climbing. Hand and Foot of Man.