STERNAL MUSCLES. 325 



There is only one single muscle inserted in both 

 the shoulder-bone and the coracoid. It has its 

 insertion in the lower side of the shoulder-bone and 

 the upper edge of the coracoid, and its tendon is 

 inserted in the head of the humerus, on the lower 

 side, by the edge of the insertion of the smaller 

 pectoral muscle. Its office is to close the wing 

 toward the body, but it of course acts only on the 

 humeral portion. 



The next set of muscles are those which are 

 attached to the scapula or shoulder-bone only, and 

 act between that bone and either the humeral or the 

 radial portion of the wing. They are three in number. 

 The first is attached to a greater or smaller portion 

 of the external edge of the scapular bone, sometimes 

 in two separate fasciculi of fibres, and sometimes with 

 the two fasciculi united by a tendinous septum. 

 When the latter is the case, it is inserted by one 

 tendon in the posterior edge of the humerus, below 

 the cavity ; and in the former, by a tendon and a 

 fasciculus of muscular fibres to nearly the same point. 

 The use of this muscle is to draw the humerus toward 

 the body of the bird, and at the same time to raise it 

 upwards. The second of these muscles is inserted 

 by a very strong tendon to the glenoid cavity, and it 

 is attached to the humerus. Its office is to draw the 

 wing toward the body, and raise it, and also to extend 

 the fore-arm, or radial joint of the wing. The third 

 of these muscles is a long and slender fasciculus, 

 which, originating in the lower and exterior part of 

 the scapular bone, behind the last-mentioned one, 

 is attached to the scapula, and appears chiefly an 

 auxiliary to the former. 



There are two muscles originating in the scapula, 

 the clavicle and the coracoid, which chiefly assist in 



