BY W. J. S. McK.VY. 341 



I n s e r t i o n. From this origin the muscle runs forward and 

 outwards as a broad band, hiding from view portion of the P. 

 major and clavicular deltoid, then running superficial to the omo- 

 hyoid and acromiotrachelien the muscle is inserted, under cover 

 of the anterior part of the trapezius, on the temporal bone dorsal 

 and immediately anterior to, the retro-temporal foramen. 



M. EPISTKRNO-CLEIDO-MASTOIDEUS. (Fig. 7, E.C.M.) 



Ornithorhynchus. 

 Origin, (a) S^ij)erficial jjoriion. — This arises from the inner 

 half of the anterior surface of the clavicle, and the anterior surface 

 of the median portion of the interclavicle between the inner 

 extremities of the clavicles. 



Insertion. From this origin, which is tendinous, the 

 muscle runs forwards and outwards and dorsally over the posterior 

 portion of the mandible and the zygomatic process, to be inserted 

 on the dorso-anterior border of that part of the squamosal that 

 stands out as a well-marked process from the skull. 



Origin, (b) Deep portion {cleido-mastoideus). — This is seen 

 as a tliin band springing from the mid-point of the anterior 

 surface of the clavicle. 



Insertion. It runs under cover of the external border of 

 the superficial portion, and winding round the posterior extremity 

 of the mandible, is inserted immediately posterior to the superficial 

 portion on the squamosal. 



Relations. At its origin its outer border is placed close 

 to the insertion of the anterior trapezius on the clavicle. 



Innervation. Echidna : N. accessorius and a branch from 

 ii. cervical nerve. Ornilltorhynchus : N. accessorius. 



Westling —Echidna : N. accessorius and branch from ii. cervical 



nerve. 



Echidna. 



Westling gives the origin from the episternum, manubrium 

 sterni, and greater part of the sternum ; and the insertion by 



