434 



mi. a. F. SONNTAG ON TH12 



The suhscapnlaris arises from tlie entire subscapular fossa, and 

 lias a great ailmixture of sti'ong tendinous fibres. The latter 

 converge and pass over the lesser tuberosity to be inserted into 

 its upper border. The tuberosity with these tendons presents a 

 full, rounded appearance. 



The su'prasjnnatus arises from the outer two-thirds of the supra- 

 spinous fossa and is inserted into the upper part of the great 

 tubei'osity of the humerus. The infraspinatus arises from the 

 outer two-thirds of the infi-aspinous fossa. It is inserted by two 

 heads into the great tuberosity of the humerus and the bone 

 beyond it, so as to displace the insertion of the teres minor 

 distally (text-fig. 12 0). 



The biceps arises b}^ two heads as in Man, the short one joining 

 the long one in the upper third of the arm. The muscle con- 

 verges to a long, flat tendon wdiich is inserted into the dorsal 



Text-figure 12. 



I.L.L. 



A : manubrium stenii of Drill ami Mandrill*. R: Hexors of elbow-joint; C: 

 muscles attached to the gv^at tuberosity of the humerus. B.A : brachialis 

 anticus ; Bi : biceps ; U.M : deltoid ; I.S : infraspinatus ; S.S : supraspinatus; 

 T.Mi : teres minor ; I.L.L : internal lateral ligament. 



aspect of the proximal part of the radius from the head to the 

 point where the bone begins to exhibit its marked forward con- 

 vexity (text-fig. 12 B). It first narrows slightly and expands 

 later. There is no bicipital fascia as in Man. 



The coraco-hrachialis has a long, powerful tendon of origin and 

 an elongated fleshy belly inserted into the shaft of the humerus 

 close to the deltoid insertion. 



The hrachiaUs anticits arises as in Man. It has a very strong 

 tendon which winds round the internal condyle of the humerus, 

 and is inserted into the upper inch of the inner surface of the 

 shaft of the idna, and the internal lateral ligament of the elbow 

 joint (text-fig. 12 B). 



The triceps is a very powerful muscle. Its long head arises 



* Vrolik states that the manubrium is abs'jnt in the Mandrill. 



