346 SHOULDER GIRDLE IN MONOTRFMES, 



Insertion. Running forwards and inwards a tendinous 

 intersection crosses the muscle, running from within outwards and 

 posteriorly. This is not seen distinctly until the muscle is 

 reflected, and then it is further seen that anterior to the inter- 

 section the muscle is cleft into two layers. The deeper (dorsal 

 one) is inserted on the basihyal, while the superficial (ventral) one 

 is continued on and is inserted into a tendinous intersection 

 common to it and the mylohyoid and stylohyoid ; some of the 

 fibres being, however, continuous without interruption with those 

 of the mylohyoid, while a few fibres are inserted on the ceratohyal. 



Echidna. 



WestlinCx gives the origin from the scapula between the siipra- 

 spinatus and the acromio-trachelien, and says that as in Ornitho- 

 rhynchus it has no tendinous intersection. Its anterior extremity 

 is split into two layers, the dorsal one of which is inserted on the 

 larynx and the hyoid ''die ventrale vereinigt sich mittelst 

 Aponeurose rait den iibrigen Zungenbeinmuskeln, urn sich an die 

 Basis der Zunge zu heften." 



Leche follows Westling. 



MlVART describes this muscle. 



Orn tthorhyxchus. 



Owen merely mentions that "the omohyoid and the mylohyoid 

 have a common insertion into the hyoid." 



CouES says the "mylohyoid and omohyoid are connected, if not 

 continuous, at the hyoid bone ; there is trace of a tendinous inter- 

 section, but the hyoid insertion (in the side of the body of the 

 V>Qjie) of the two is identical, and some at least of the muscular 

 fibres are not interrupted." In another place he says, " the omo- 

 hyoid is continuous with the mylohyoid at its hyoid point of 

 insertion, and there is no division into two bellies by a tendinous 

 intersection, nor any confining of the muscle in its continuity by 

 an aponeurotic pulley. Above it is partly divisible into two 

 fasciculi, the smaller internal one of which is inserted lower down 

 on the hyoid than the other, and is distiiict from mylohyoid." 



