CHURCH ON THE MYOLOGY OF THE ORAKG TJTANO. 513 



body when the animal is climbing. Corresponding modifications 

 will be found in the posterior extremities. 



The Teres Major was proportionately a stronger muscle than in 

 man, and its tendon was inserted over a space of one inch and three- 

 eighths : this was partly caused by its receiving a slip, as before 

 mentioned, from the Latissimus Dorsi. 



The Teres Minor differed only in its mode of origin ; arising be- 

 tween the long head of the Triceps and the Infra-Spinatus muscles 

 from the inferior border of the scapula. 



The acromial portion of the Deltoid was inserted separately into 

 the humerus by a thin tendinous band, while the mass of the muscle 

 was inserted into the deltoid tuberosity, which was situated lower 

 down the arm than in man. 



In the Magot, it was divided, as stated by Duvernoy, into three 

 almost distinct portions, which he calls Claviculaire, Coracodienne, et 

 Sous-epineuse. 



The Pectoralis Major arose by three distinct heads ; one coming 

 from the clavicle, the other two from the sternum and intercostal 

 cartilages. The upper sternal portion did not, in this instance, reach 

 higher than the third rib. The lower sternal portion arose from the 

 costal cartilages, the ensiform appendage, and the sternum : it re- 

 ceived, opposite the fifth rib, some fibres from the external oblique. 

 The muscle was inserted by a broad tendon, extending from the 

 anatomical neck, 2-§- inches down the anterior border of that bone. 

 The fibres of the clavicular portion form the lowest and those of the 

 lower sternal portion, the upper part of the tendon, as in man. 



In the Chimpanzee (Yrolik, 1. c. p. 18), this muscle has only a 

 single sternal and clavicular origin. And Prof. Owen* describes it as 

 formed in the Orang of sterno-humeralis, costo-Jiumeralis, and sterno- 

 costo-humeralis portions — apparently, therefore, in his specimen, the 

 clavicular portion was wanting ; neither does Sandifort mention any 

 clavicular portion in the adult dissected by him. 



In the Magot, a thin muscular slip, distinct from the Feet. Major, 

 and beneath it, was found, which arose from the lower ribs, and 

 terminated in a thin membranous expansion, which appeared to be 

 inserted partly into the aponeurosis of the arm, and partly into the 

 intermuscular septum and the humerus. 



In Man, it is by no means unfreqj.ent to find the sternal portion 

 divided into two or more parts ; the arrangement met with in the 

 Magot is described in the human subject by Theile ;f and Mr. Hal- 

 lett % mentions a very similar one as occurring in man. 



The Pectoralis Minor presented the same appearance as in man ; 

 in the Grorilla, Duvernoy states that it is divided into two portions ; 

 one passing'in front of, the other behind the laryngeal sac. 



The two* heads of the Biceps remained distinct until they reached 



* Proceedings of the Zool. Society, vol. i. p. 19. 



f Encyclopedic Anat. torn. iii. p. 202. 



% Mr. C. J. Hallett, Edinburgh Medical and Surgical Journal, 1847. ' 



