10 



Leach, The Myology of the Bell-Magpie. [,^'^l\- 



2^. The genio-hyoideus \j^a] [15], as already mentioned, differs 

 in a marked manner in Strepera from the same muscle in the 

 Raven. The Austrahan Raven agrees closely with the American 

 Raven as described by Shufeldt. In Strepera, Gymnorhina, and 

 Cracticus, an external branch arises from the bare part of the 

 outer surface of the mandible just behind the horny sheath. It 

 runs backwards, crosses the lower edge of the mandible, and runs 

 obliquely backward to join the larger branch, where it is wrapped 

 round the thyro-hyal. It undoubtedly assists this muscle in 

 pulling the tongue forward. Professor Gadow figures a similar 

 external branch for a Cockatoo, a Bustard, and a Duck in Bronn's 

 " Klassen VI. Band," plate xxxii. 



The main division of this muscle arises, as Shufeldt describes for 

 the American Raven, from the inner side of the mandible nearly 

 as far forward as the horny sheath, and is wrapped round the 

 thyro-hyal as he described. It is bounded internally by the 

 mylo-hyoideiis (21), which arises above it and passes over it to 

 the middle line. 



24. The cerato-hyoideus [15] is in Strepera as Shufeldt describes 

 it for the American Raven. Arising from the thyro-hyal, it is 

 inserted by a line, stiff tendon on a bony tubercle on the cerato- 

 hyal. The Australian Raven agrees in the position and course 

 of this muscle, but differs in having a fleshy insertion. Gymnorhina. 

 and Cracticus agree with Strepera. 



25. The sterno-hyoideus [6] [ba] in Strepera arises fleshy on each 

 side from the anterior edge of the superior larynx. The two 

 muscles run directly forward to meet at the base and be inserted 

 together into the cerato-hyal. The cleido-trachealis (8) on each 

 side, however, instead of being inserted in the cerato-hyal just 

 to the outer and lower side of each sterno-hyoideus, as it is in the 

 Australian Raven, joins the corresponding sterno-hyoideus in 

 Strepera, Gymnorhina, and Cracticus at about one-third of its 

 length from its origin. Shufeldt found that the cleido-tracheales 

 (8) in the American Raven are different. He says the cleido- 

 tracheales " are finally inserted, touching each other by their inner 

 borders on the anterior aspect of the superior larynx, the trachea, 

 and the skin over these parts." Shufeldt found that some fibres 

 of the sterno-hyoideus (25) were continued into the soft part of 

 the tongue in the American Raven. No fibres going into the soft 

 part of the tongue were observed in any of the birds dissected. 



26. The depressor-glosstts [16] is a short muscle in the middle 

 line on the under side of the tongue. It arises, as Owen and 

 Shufeldt describe, on the under surface of the basihyal. The 

 fibres contract, and become tendinous, to be inserted at the tip 

 of the tongue bone. 



27. The cerato-glossal [17] is a small muscle arising on the upper 

 surface of the basihyal and running to the thyro-hyal. Owen 

 describes it similarly for the Fieldfare. 



