222 MARSHALL— A STUDY OF THE [June i 9 , 



from about the lower half of the keel and from that portion of the 

 body of the sternum not appropriated by the above muscle. The 

 fibers converge to a line which is dorsal to the mid-line, passing 

 over into a strong flat tendon that bends around to the inner sur- 

 face of the coracoid. The tendon goes through the foramen trios- 

 seum and is attached to the humerus on its dorsal projection. 



3. Coraco-brachialis posterior (Cor. br. p., PI. VI, Figs. 25, 26, 

 30). When the m. pectoralis is turned back this small muscle is 

 seen extending out from under the supracoracoideus. It arises 

 from the dorsal proximal half of the border of the coracoid. The 

 fibers converge to form a short strong tendon which is attached to 

 the antero-ventral margin of the humerus just anterior to the 

 pneumatic foramen. 



B. Other trunk muscles inserting on wing, scapula and coracoid. 



1. M. delioideus major (PI. V, Figs. 16, 22). This muscle 

 consists of an anterior and posterior portion. The delicate an- 

 terior part {Del. a.) arises fleshily from the inner surface of the 

 clavicle and the neighboring portions of the scapula. It emerges 

 from the foramen triosseum, crosses the tendon of the m. supracor- 

 acoideus, runs entirely around the projection to which the tendon 

 of the muscle is attached, and makes a fleshy insertion at the base of 

 the anterior border of the humeral crest. 



The large posterior portion (Del. p.) springs from the dorsal 

 border of the clavicle and adjoining dorsal surface of the scapula. 

 It passes obliquely downward and is inserted fleshily on the humeral 

 crest and along the shaft of the humerus for about one half its 

 length. This differs somewhat from Gadow's description. 



2. M. delioideus minor. This muscle could not be made out, 

 therefore is probably absent. 



3. M. latissimus dorsi (PI. V, Figs. 17, 22 ; PI. VI, Fig. 26). 

 This is the most superficial muscle of the back, and is revealed by 

 the removal of the skin. It consists of two portions, a very thin 

 anterior layer and a much larger and stronger posterior muscle 

 bundle. 



The anterior portion (Lat. d. a.) arises from the spine of the 

 last cervical vertebra and from the spines of the two following 

 dorsal vertebras. The fibers pass in a transverse direction over the 

 scapula, converging somewhat after crossing it, and diverge as they 



