BY W. J. S. McKAY. 357 



S. S<\ M. subscapularis. 



S. S. M. supraspinatus. 



T. M. M. teres major. 



Ti. Tendinous intersection in P. major. 



Tr. A. M. trapezius, anterior portion. 



Tr. P. posterior portion. 



Trc. S. M. triceps, scapular portion. 

 Trc. H. humeral portion. 



DESCRIPTION OF FIGURES. 



Fig. 1. — (Echidna). The abdominal panniculus (P«. ^.) is seen running 

 forward and dividing into a superficial (Pii.S.M., Pn. S.E.) 

 and a deep layer [Pn. D. /. ) ; this latter part runs to be 

 inserted on the greater tuberosity, and constitutes a "dermo- 

 flexor brachii." The clavicular deltoid {Dlt. C. ) is seen 

 superficial to the pectoralis major {Pt. M.). Gl. is a large 

 gland, superficial to the sterno-mastoid {S.M.). The P. 

 quartus [Pt. Q ) is seen quite distinct from the P. major 

 (Pt. M.) and lying superficial to its postero-external border. 



Fig. 2. — (Echidna) . The deep portion of the panniculus (Pn. D. i. ) shown 

 in fig. 1 is raised, and its deep layer is shown (Pn. D. ii.). 

 Between these two layers lie the P. quartus (Pt. Q.) and 

 P. major (/'<. M.). 



Fig. 3. — (Echidna). The deep layer of the panniculus (P/i. Z). ^. ) is pinned 

 back, and the cleft tendon of insertion of the P. quartus is 

 shown (Pt. Q., Pt. (). i.) embracing the tendon of insertion 

 of the y. major (Pt. M.). The edge of the latter 

 muscle is shown to be placed deeper than the postero- 

 internal edge of the clavicular deltoid iDtt. C.) The P. 

 quartus is seen arising in part from the metasternum (Mt.S.), 

 but chiefly from the aponeurosis of the external oblique 

 (Ex. 0.). The pyramidalis (Py.) is shown to be inserted on 

 the metasternum, and the rectus is seen cleft into a super- 

 ficial (Ret.) and a deep layer (Ret'.). CI. is the clavicle ; 

 /. CI. the interclavicle or episternum. 



Fig. 4. — (Echidna). The P. major, P. quartus, and deep panniculus are 

 reflected ; and the manner in which the latter muscle 

 embraces the other two is shown. The clavicular deltoid 

 (Dlt. C-) is raised, and we thus see the epicoraco-humei'al 

 (Ep. //.), and the supraspinatus {S. S.). The epicoracoid 

 head and the coracoid head of the biceps have been cut 

 through, and the relation of the former to the tendon of the 

 rectus (Ret.) is shown. The coraco-brachialis brevis is seen 

 inserted into the humerus. The relation of the two parts of 

 the biceps as they run to be inserted is shown to the 

 right of the figure. 



Fig. ^A.— (Echidna). Outline from Westling. Tafl. ii., fig. 6. Ep. epicora- 

 coid. Ep. St. episternum. M. .V. manubrium sterni. Ri., 



