PWYHlOUXiY, ANJj PATJIOLOGY OF THE CJIIMPANZEE, 347 



process, and it is iiiser-ted into an impression over an inch long 

 on the inner aspect of the shaft of the humerus. In its upper 

 part it is separated by a cellular interval into two parts, and the 

 musculo-cutaneous nerve passes through the gap. Ko coraco- 

 brachialis brevis was present. Some fibres go to the internal 

 intermuscular septum and dorso-epitroch lean's, and Hepburn (24) 

 suggests that these represent the coraco-brachialis longus. The 

 part running to the inner surface of the shaft of the humerus 

 corresponds to the coraco-brachialis medius. No coraco-brachialLs 

 brevis was recorded by CJhampneys (llj, Bland-Hutton C4), 

 Dwiglit dSj, and Wilder (53), but it was seen by Macalister (33) 

 and Hepburn (24j. Blaud-Sutton gives its insertion into the 

 upper third of the shaft of the humerus and the capsular liga- 

 ment. Wilder states that it arises from the coracoid process 

 through the medium of the short head of biceps. 



The biceps arises as in Man, but the bellies remain separate till 

 they reach the junction of the lower and middle thirds of the 

 arm. In the upper part of the forearm there is a slight bicipital 

 fascia (lacertus fibrosus). The muscle fibres of th'e combined 

 bellies end in a stout, ribbon-like tendon which is inserted into 

 the posterior part of the radial tuberosity. 



The hrachialis o/aticus is connected by a strong fascial band to 

 the pectoralis major near its insertion. The origin is as in Man 

 and embraces the insertion of the deltoid. A slip is given to the 

 fascia of the forearm. The fibres converge to an insertion into 

 the coronoid process and inner border of the olecranon. 



The dorso-ejAtrochUariH is a thin muscle, a little more than 

 half an inch wide, sprinpring fiom the junction of the muscular 

 and tendinous parts of the latissimus dorsi. Fibres pa.ss into its 

 upjier part from the coraco-brachialis. It passes into the inner 

 side of the internal intermuscular septum in the lower third of 

 the arm, and the latter connects it to the internal condyle. 



The tricepH differs considerably from that in Man. The long 

 head arises from the dorsal aspect of the outer quarter of the 

 axillary border of the scapula. The outer head arises from the 

 upper extremity of the shaft of the humerus and lower part of 

 the capsule of the shoulder joint. The inner head arises from 

 the proximal third of the shaft of the humerus along a linear 

 strip. After a course of two inches the long and outer heads 

 fuse to form a fleshy belly, and this receives the inner head an 

 inch more distal. The muscle is inserted by muscular and ten- 

 dinous fibres into the tip and dorsal surface of the olecranon, 

 a bursa intervening between the muscle and the capsule of the 

 elbow joint. 



A broad bundle of fibres arising from the deep surface of the 

 distal half-inch of the triceps runs to the capsule of the elbow 

 joint and represents the svhamconeus . 



Champneys (11) states that the triceps, anconeus, and sub- 

 anconeus are as in Man. Hepburn (24) mentions that the 

 triceps is as in Man except for the outer head, and mentions 

 that the anconeus is present. 



