BY W. J S. lIcKAY. 305 



coraco-brachialis longus unci einen M. coraco-brachialis brevis, 

 welche sowolil betretfs des Ursprungs wie der Insertion mit 

 denselben bei Ecliidna iibereinstimnien." 



As regards the epicoraco-brachialis, we think that there are 

 sufficient grounds for regarding it as a " coraco-brachialis." In 

 the Echidna it is a very distinct separate muscle, and its nerve 

 supply is from a branch, not from the musculo-cutaneous, but 

 from the cord common to it and the musculo-cutaneous nerve. 

 But in Ornitliorhynchus the muscle is not so distinctively a 

 separate muscle, and although the chief nerve to it corresponds to 

 the nerve in Echidna,, at the same time the true musculo-cutaneous 

 nerve gives it a distinct twig. It will be seen by referring to 

 Westling's figure (Fig. 17, CI.) of the brachial plexus in Ornitho- 

 rhynchus, that she found the muscle supplied from the musculo- 

 cutaneous nerve alone. She says ..." ein Nerv, der sich 

 in die beiden Portionen des M. biceps brachii, den M. coraco- 

 brachialis und den M. epicoraco-brachialis vertheilt." 



M. INFRASPINATUS. 

 Echidna et Ornithorhyxchus : AI. infraspinatus, all authors. 

 Echidna. 



Origin. This muscle has an extensive origin from the outer 

 face of the scapula. The surface of bone from which it arises is 

 bounded as follows : dorsally by the anterior part of the outer rim 

 of the vertebral border (excepting the small area from which the 

 clavicular deltoid arises) ; anteriorly by the inferior part of the 

 spine and the outer border of the acromion ; while posteriorly by 

 the ridge from which the teres minor arises, and the upper two- 

 thirds of the glenoid border. 



Insertion. The muscle runs downwards and outwards to 

 be inserted by a narrow tendon, as well as by muscular fibres, on 

 the posterior face of the humerus, just internal to the proximal 

 third of the pectoro-deltoid ridge ; the insertion being hidden by 

 the clavicular deltoid, and being in immediate relation with the 

 insertion of the upper layer of the deep panniculus. 



