258 MK. G. p. MUDGE ON THE MYOLOGY 



Sternohyoideus. 



This muscle arises from the anterior end of the ventral border of the sternal carina, 

 and passing forwards along the ventro-latcral aspect of the trachea, on either side, it 

 ])asses between the ceratoliyoideus and posterior mylohyoideus, whence it reaches the 

 dorsal surface of tlie hyoid and its insertion into the posterior portion of the outer 

 margin of the pavahyal processes. In some instances the insertion extends backwards 

 along tlie body of the basihyal and may even reach to some distance along the hypo- 

 branchial. In but very few Parrots {Eos, Ftistes, PsHtacus, Fezo2)orus, Strinr/ops, and 

 Aprosmicius only) is it a continuous muscle from its origin to its insertion ; in the 

 majority, the middle portion of that part which extends along the neck is either 

 exceedingly attenuated — represented by a few scattered fibres on the skin — or is quite 

 retrogressed; even in Eos and Aprosmictus the greater portion of it is attached to the 

 skin of the neck. In a few its origin has retrogressed, and iu others distinct evidences 

 of retrogression may be seen at one part or another of its course. 



In Coracopsis, Microglossus, Cacatua roseicajpilla, C. sulpkurea, C. alba, C. iriton, 

 and Eclectus (text-fig. 7, p. 231) the insertion of the muscle is upon the parahyal 

 process with an extension backwards to the inner surface of the hypobranchial. The 

 muscle divides just before reaching its insertion, the anterior branch becoming inserted 

 to the dorso-lateral surface of the parahyal process and the posterior to the inner 

 surface of the hypobranchial. In Cacatua triton the extension is along a little more 

 than the anterior third of the hypobranchial, and is greater than in any other Parrot ; 

 in C. roseicapilla and C. alba the two branches are connected by an intermediate piece 

 of connective tissue, and the posterior branch (that inserted on the hypobranchial) 

 shows signs of retrogression ; in C. sulphurea the hypobranchial insertion is only 

 represented by a few muscular fibres, it having xmdergone a great amount of retro- 

 gression. In Microglossus the hypobranchial insertion is between the ceratoglossus 

 superior and the hypoglossus obliquus, instead of to the inner side of the former muscle. 

 In Eclectus (text-fig. 7, p. 231) the parahyal insertion is very broad and extends 

 along the whole length of the parahyal process, while the hypobranchial portion 

 exhibits signs of retrogression as it turns round the ceratoglossus lateralis. In 

 all other Parrots the hypobranchial insertion has disappeared. In Pyrrkulopsis the 

 insertion of the muscle into the parahyal process extends backwards along the dorsal 

 surface of the body of the basihyal to the posterior extremity of that. In all other 

 Parrots, Lorms (PL XXVII. fig. 21, s.h.) and Eos excepted, the insertion of the muscle 

 is restricted to the parahyal process, and usually to its posterior half; sometimes it is 

 inserted into the lateral surface, and more rarely into the dorsal surface. Iu Chrysotis 

 viridigena, Eclectus, and Cacatua galerita the insertion extends up to the anterior 

 extremity of the parahyal process. In Lorius domicella (PL XXVII. fig. 21) and 

 L. flavo-palliatus the muscle is inserted to the posterior two-thirds of the parahyal 



