278 SHOULDER-GIKDLE IN MONOTREiMES, 



der lang unci scbmal ist. Der gauze Muskel inserirt am Tuber- 

 ciilum majus, dorsal von dein Zipfel des Pauniculus carnosus, den 

 Fewkes M. dermo-brachialis anterior geuannt hat, und ventral 

 vom M, dermo-brachialis posterior desselben Forschers. Eine 

 claviculuare Portion felilt, scheint aber von der medialen Portion 

 des M. deltoideus ersetzt zu sein ; vergleiche die Beschreibimg des 

 letztgenannten Muskels. Innervation: Nn. Cervicales v. und vi." 



Lechb follows Westling and remarks that a clavicular portion 

 is absent, but appears to be replaced by the median portion of the 

 deltoid. 



MiVART describes the P. major as arising from the sternum, 

 median portion of the interclavicle, " and also somewhat from the 

 aponeurosis of the external oblique, but not at all from the 

 clavicle, or from the lateral branches of the interclavicle." 



MivART mentions the fact that the insertion is between the 

 layers of the panniculus. He makes no mention of P. quartus as 

 distinct from the P, major. 



Owen says of the P. major in Ornithorhynchus, " the ]iectoralis 

 is of very striking dimensions, the origin of the superficial portion 

 extends from the acromion, along the sternum and liiiea alba 

 almost to the pubes ; a deeper-seated portion arises from the 

 osseous sternal ribs ; the fibres of both portions converge to be 

 inserted on to the largely developed pectoral or anterior crest of 

 the proximal half of the humerus." 



Smith gives a description of the P. major : " Prolonged inwards 

 from the pectoral ridge of the humerus is a tendinous band 

 passing transversely towards the mid-sternum. To the upper 

 (anterior) border of this band and ridge the clavicular and 

 anterior sternal fibres of the P. major radiate to be inserted, 

 while to its lower (posterior) border are attached at its inner end 

 the posterior sternal fibres of the pectoralis, then the P. quartus, 

 and external to this the dermo-flexor brachialis. The P. quartus 

 is a thin muscle arising from the fascia of the abdominal muscles, 

 having its inner border touching the posterior edge of the P. 



