474 University of California Publications in Zoology [Vol. 13 



the scapula; it is inserted into the lateral surface of the deltoid 

 tuberosity of the humerus. 



h. Spinodeltoideus arises from the spine and acromion of the 

 scapula, and is inserted with 14a-. The deltoids abduct and draw 

 forward the humerus. 



15. Abductor brachii inferior (ab. br. in., fig. Q), corresponds 

 to the scapular part of the deltoid in man. It is a thin sheet of 

 muscle covering the infraspinatus; it arises on the spine of the 

 scapula for almost its entire length, and from the fascia of the 

 infraspinatus, and is inserted on the deltoid tuberosity with the 

 deltoids. This muscle assists in flexing and abducting the humerus. 



16. Supraspinatus {supras., fig. S) is peculiar in being divided 

 into two parts, a superior and an inferior. The superior part is 

 the larger and arises from the dorsal third of the supraspinous 

 fossa {supras., pi. 38). The inferior part arises from a narrow 

 line on the dorsal surface of the base of the proximal two-thirds 

 of the spine of the scapula. The two parts join in a common 

 tendon which is inserted on the greater tuberosity of the humerus. 

 This is a strong muscle in the gopher; its action is to extend the 

 humerus. 



17. Infraspinatus (infras., fig. S), arises from the proximal 

 third of the infraspinous fossa and from the base of the proximal 

 two-thirds of the spine of the scapula. It is inserted on the greater 

 tuberosity of the humerus just caudal to the insertion of 16 

 {infras., pi. 38). The infraspinatus flexes the humerus with rela- 

 tion to the scapula. 



18. Teres major {ter. ma., flg. T) arises from an impression on 

 the proximal one-fourth of the axillary border of the scapula {ter. 

 ma., pis. 38, 39). The flbers pass ventrad and mesiad and join the 

 latissimus dorsi in their lower third. The combined tendon passes 

 to the mesial side of the humerus and is inserted just below the 

 lesser tuberosity. The teres major is one of the flexors of the leg. 



19. Teres minor {ter. mi., flg. S) is closely related to the 

 infraspinatus. It arises along the axillary border of the scapula 

 on the lateral surface, and is inserted on the greater tuberosity of 

 the humerus behind the insertion of the infraspinatus {ter. mi., 

 pi. 38). It is an unimportant flexor of the leg. 



20. Subscapularis {subsc, fig. T) covers the whole of the 

 mesial surface of the scapula, arising from the proximal fourth of 

 this surface and from a line along the axillary border {subsc, 



