MYOLOGY 



39 



and the cranial portion of the xiphoid, practically the 

 entire muscle lying deep to the superficial pectoral. In- 

 sertion is by aponeurosis along the deltoid ridge, the base 

 of the greater tuberosity, and upon the extreme lateral end 

 of the clavicle. 



M. pectoralis abdominalis (figs. 7, 29) corresponds to 

 what is sometimes called the xiphihumerahs. It has 

 origin upon the midventral line from a trifle craniad of the 

 posterior termination of the profundus posterior caudad for 

 a distance of 18 mm.; thence by fascia, origin extends 



longis. dorst 





'^^''■'i'''PC4 





tnagnt^s 



Fig. 9. Subscapular and thoracic musculature on right side of Teonoma, 

 with scapula removed (a showing position of scapular border). 



directly laterad as far as the abdominal external oblique. 

 This muscle is at first ribbon-like but soon contracts, be- 

 coming triangular in cross section, and is inserted upon the 

 head of the humerus mediad of the insertion of the pro- 

 fundus anterior division. 



In Neotoma it is not so well developed, the insertional 

 end especially being w^eak. In Teonoma it is more sharply 

 triangular. 



M. subclavius (figs. 7, 29) is the only portion of the 



