MUSCULAR SYSTEM OF MAMMALIA. 31 



of that part only which is called the ascending portion in the 

 human subject, and which is inserted into the posterior margin 

 of the spine of the scapula. The ( sterno-mastoid ' is present, 

 but the ' levator anguli scapulae,' the cleido-mastoid, and the 

 clavicular portions of the trapezius and deltoid are all replaced 

 by the muscular expansion which, taking its origin from the par- 

 occipital and from the transverse processes of some of the superior 

 cervical vertebrae, passes downward in front of the head of the 

 humerus and descends along the inner surface of the fore-arm, 

 into which it is ultimately inserted. 



The ' trachelo-acromialis ' arises from the transverse process of 

 the atlas and of the four following cervical vertebrae, descends toward 

 the shoulder-joint, making its appearance externally between the 

 two divisions of the trapezius, which it separates ; it then spreads 

 out over the acromial portion of the scapula, and descends as far 

 as the middle of the humerus. This muscle draws the shoulder 

 upward and forward in the Tapir, and is implanted into the 

 aponeurosis which covers the deltoid: while, in the Horse, it 

 has its insertion into the middle portion of the humerus by 

 two aponeurotic tendons, which embrace the brachialis internus 

 muscle. 



The e serratus major anticus ' arises from the transverse pro- 

 cesses of the third, fourth, fifth, and sixth cervical vertebrae, and 

 also from the external surfaces of the six superior ribs : its origins 

 extending as far backward as the insertion of the tendons of the 

 sacro-lumbalis : from this extensive origin it passes backward 

 around the chest to be implanted into the base of the scapula, its 

 insertion occupying nearly half of the internal surface of that 

 bone. It forms, with its fellow on the opposite side, a kind of 

 sling, by which the trunk is suspended. 



The ' pectoralis minor ' is represented by a muscle, which, arising 

 from the sternum and from the first, second, third, and fourth 

 ribs near their sternal terminations, runs upward and backward to 

 be inserted into the superior costa of the scapula near the base 

 of that bone; it also contracts tendinous attachments with the 

 aponeurotic covering of the teres minor and other scapular 

 muscles. 



The * rhomboideus ' arises entirely from the ligamentum nuchae, 

 and from the spines of the anterior dorsal vertebrae, whence it 

 runs outward to be affixed to the base of the scapula. 



The ' omo-hyoideus ' is represented by a strong muscular fasci- 

 culus, from the coracoid tubercle. 



