314 SHOULDER-GIRDLE IN MONOTREMES, 



muscle occupying the internal face of the scapula in its proper 

 position. 



M. TERES MAJOR. 



Echidna : Teres major, single, all authors. 



Ornithorhynchus : Teres major, double = Teres major proper + Exter- 

 nal part of nibscapularis, Meckel and Owen ; Teres major double = Teres 

 inajor proper + External and internal parts of M. svbscaptdaris, Coues ; a 

 single muscle, the teres major p>roper, Cuvier and Laurillard. 



ECHIDXA. 



Origin. The teres major arises from a small area on the 

 posterior end of the vertebral border of the scapula. 



Insertion. The muscle, cylindrical in shape, runs down- 

 wards and outwards to be inserted into the distal part of a trian- 

 gular flattened surface, whose base is continuous with the lesser 

 tuberosity, and whose apex merges into the sharp internal border 

 of the humerus. 



Relations. At its origin the muscle is intimately connected 

 with the slip from the scapula to the latissimus dorsi. The muscle 

 in its course is hidden from view and cannot be seen till the sub- 

 scapidaris in front and the slip to the latissimus posteriorly are 

 drawn apart. (Fig. 10). At its insertion the tendon contains a 

 small sesamoid bone. 



ORNITHORHYNCIirS. (Fig. 12, T. M.). 



Origin. The teres major arises from the posterior third of 

 the external margin of the vertebral border, and from the immedi- 

 ately adjoining face, of the scapula. 



Insertion. The muscle runs as a fleshy belly downwards 

 and somewhat outwards, and becoming narrower as it approaches 

 its insertion, by a well marked tendon, about the mid-third of the 

 inner border of the humerus, immediately distal to the insertion 

 of the subscapularis. 



Pv e 1 a t i o n s. At its origin the muscle overlies the subscapu- 

 laris as it arises from the outer surface of the scapula. It is 

 intimately connected with the fine tendon of insertion of the costal 



