MYOLOGY OF THE ORNITHORHYNCHUS . 145 



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joint behind to be inserted, chiefly fleshy, into the posterior tubercle 

 upon the head of the humerus. It rotates the bone inwards, feebly 

 counteracting the two preceding muscles. 



Teres major. Double ; both portions of great size, and perfectly 

 distinct. The lower, or teres major proper, arises fleshy from the 

 posterior extremity of the scapula for about one-third of an inch ; it 

 lies at first upon the serratus magnus, and then along the superior 

 border of the latissimus, forming a great pyramidal muscle running 

 between the last and the upper teres, rapidly narrowing to a rather 

 long, stout, flattish tendon that passes behind (mesiad of) the scapular 

 head of the triceps, to be inserted in the posterior ridge of the hume- 

 rus, one-half inch or more above the insertion of the latissimus. On 

 its deep surface muscular fibres reach nearly to its insertion ; on the 

 superficial aspect, the large glistening tendon radiates nearly half way 

 to origin. The upper portion is still larger, and has more extensive 

 and complicated origin from both " sides " of the scapula, which is 

 thus, as it were, embraced by the muscle. The outer origin is from the 

 postero-external aspect of the scapula, from the origin of the lower 

 teres to that of the scapular head of the triceps ; the inner origin is 

 thinner and more extensive and fleshy, from the whole surface of 

 bone between the insertions of the two digitate sets of levatores scap- 

 ulae. The muscle is pyramidal in shape, like, and with the general 

 aspect of, the preceding, and with precisely similar tendinous arrange- 

 ment. But it is inserted much higher up, in immediate relation with 

 the shoulder-joint, into the posterior tubercle of the humerus, along- 

 side the insertion of the muscle above called subscapularis. N. B. 

 Its tendon contains an articular sesamoid bone. 



Two perfectly distinct muscles besides the one above called "ante- 

 rior deltoid" proceed from the coracoid apparatus to the humerus; 

 they have together been considered as coraco-brachialis, but the 

 name is properly applicable to only one of them. 



Coraco-brachialis proper. This is the posterior, and the longer and 

 slenderer of the two. It arises by a very short tendon in common 

 with the larger moiety of the biceps, from the sternal extremity of 

 the coracoid ; quickly enlarges to form a flattened-fusiform muscular 

 belly, representing the postero-internal margin of the arm ; it is over- 

 laid by the greater moiety of the biceps, itself overlying at first, the 

 muscle next below described, and afterwards the tendon of the la- 

 tissimus, which it crosses at right angles. Its insertion is fleshy and 

 with a very short tendon, into the lower part of the entocondylar 

 ridge of the humerus, nearly opposite the foramen : its outer surface 

 of insertion is in relation with the pronator radii teres. 



Epicoraco-brachialis. Much larger than the other, and with differ- 

 ent origin, course, relations and insertion ; lying partly upon and 



