Vol. XIV. 



1914 



] Leach, The Myology of the Bell-Magpie. 



Its fibres run to the middle line, spreading out fan- wise, and 

 meeting the fibres of the corresponding muscle of the other side 

 in a faint raphe. It covers the superior larynx, and is joined by 

 a thin fascia to the mylo-hyoideus (21), another superficial muscle. 

 Each passes directly beneath the base of the tongue, and is united 

 to it by fascia ; it is also united to the long branch of the hyoid. 

 Shufeldt refers to it as " this extremely attenuated muscular 

 stratum." It is such in Strepera also. 



The Muscles of the Tongue. 



The muscles of the tongue in Strepera show very interesting 

 departures from those of the American and Australian Ravens. 

 The Australian Raven agrees with the American Raven as 

 described by Shufeldt. The Strepera differs, however, in having 

 two divisions of the genio-hyoideus (23) and in the union of the 

 sterno-hyoideus (25) with the cleido-trachealis (8). 



Gadow (Bronn's " Klassen VI. Band," plate xxxii.) has figured 

 the external branch of the genio-hyoideus (23) on several birds, 

 including a Cockatoo {Microglossits aterrimus), a Bustard {Otis 

 tarda), and a Duck {Fuligula atra). It is interesting to find this 

 external branch present in Strepera, Gymnorhina, and Cracticus, 

 but absent in the Ravens. 



The muscles of the lingual apparatus are numbered and named 

 by Shufeldt as follow : — 



21. The mylo-hyoideus. 



22. The stylo -hyoideus. 



23. The genio-hyoideus. 



24. The cerato-hyoideus. 



25. The sterno-hyoideus. 



26. The depressor-glossus. 



27. The cerato-glossal. 



21. The mylo-hyoideus [11], a thin, sheet-hke muscle, arises 

 from near the inner upper margin of the mandible. It rises above 

 the genio-hyoideus (23) in Strepera and the Australian Raven. 

 The latter muscle is pressed close to the inside of the mandible, 

 and the mylo-hyoideus is forced to pass over it and then dip down 

 to spread out beneath the tongue. Shufeldt found it arose in 

 the American Raven " just above the lower border and the in- 

 turned edge of the horny sheath of the beak," and figures it as 

 arising close to the inner lower edge of the mandible. He speaks 

 of its " wonderfully delicate fibres." The muscle unites with its 

 fellow in the middle line, and is bound in a fascia about the base 

 of the tongue, though no definite insertion in the hyoid could be 

 found. As already mentioned, this muscle is united by a thin 

 fascia with the digastric (20). 



22. The stylo-hyoideus [14a] arises on the outer side of the 

 posterior end of the mandible. It is a flat, ribbon-like muscle, 

 running downward and forward to be inserted tendinously on 

 the thyro-hyal on the upper surface. 



