4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 80 



was several centimeters long, and upon it was directly inserted the 

 pectoralis major, without accessory attachment to the bone. The 

 dorsomedial border of the proximal third of the fleshy portion of 

 this biceps head was fused with the ventral border of the dorso- 

 epitrochlearis and medial intermuscular septum, and a slender ten- 

 don, extending along the dorsomedial border of this biceps head, 

 fused with the other slender tendon continuing distally from the 

 dorsoepitrochlearis, attached to the epicondyle. Below the point of 

 fusion the more dorsal fibers of the distal part of this biceps arose 

 from the above common tendon. The two heads of the biceps fused 

 at about the middle of the brachium, but the humeral head again 

 separated at the point where the insertional part of the long head 

 became tendinous, and the humeral head, passing medially upon the 

 antibrachium, was inserted neither by a lacertus nor upon the ulna, 

 but powerfully and fleshily into the substance of the flexor digitorum 

 sublimis going to the fourth and fifth fingers, the fibers of the two 

 muscles being uninterruptedly continuous. Thus the humeral biceps 

 and the superficial digital flexor may act as one continuous, long 

 muscle. 



M. coracohrachialis medius. — No profundus (brevis) was present 

 and the musculocutaneous nerve passed neither through the muscle 

 nor between it and the bone. In other words, the nerve passed en- 

 tirely medial and superficial to the coracobrachialis without crossing 

 the brachium. The muscle arose broadly and almost entirely fleshily 

 from the coracoid. The insertion was in no part upon the latissimus 

 tendon, as has been stated by Kohlbriigge (1890), but began upon 

 the bone of the humeral shaft immediately adjoining the termination 

 of the latissimus tendon along its distal third, and thence for a dis- 

 tance of 48 mm. 



M. hrachialis. — This was represented almost entirely by the inter- 

 nal head, origin beginning 23 mm. above and medial to the deltoid 

 termination, which continued unusually far down the arm in this 

 animal. Insertion was as usual upon the ulna, broad, and partly 

 fleshy. 



There was no trace of an efitrochleo-anconeus. 



Pithecus rhesus. — Carnegie Lab. Embryol., female, with hum- 

 eral length of 131 mm. ; left side. 



M. biceps hraehii, capita longuni et breve. — In the macaque the 

 attachments were found to be as usual, origin being from the glenoid 

 border and the coracoid, respectively, and insertion tendinously uj^on 

 the bicipital process of the radius. The bicipital groove was shallow, 

 and both bellies were relatively much more slender than in the chim- 

 panzee. Both heads were of equal size and separable to within a 



