MOEPHOLOGY OF CRANIAL 31US('LKS IN SOME YEETEBRATES. 249 



the whole muscle is a complex of muscle-metameres,i but this 

 inference is not borne out by study of its development. 



In Gallus the upper ends of the first and second branchial 

 myotomes separate from the parts beneath on the fourth day 

 (Text-figs. 72, 7o). They fuse together and extend back- 

 wards in the neck (Text-fig. 74) forming the trapezius 



Text-fig. 64. 



^-L^o'Ji 



64. 



Text-figs. 64-69. — Chvyseiiiys. embryo 8 mm. Text-fig. 64 is the 

 most anterior ; Text-figs. 64 and 65 are tliroiigli the hyoid 

 segment. Text-fig. 6i) tln-ongh the first bra.ncliial. Text-fig. 67 

 througli the second l)ranehia]. Text-fig. 68 thvoiigh the third 

 In-anchial, and Text-fig. 69 throngh the fourth branchial seg- 

 ment. 



(Cucullaris of Fiirbringer). The lower end of the first 

 branchial myotome forms the interarcualis ventralis I s. 



' " So entstand ein nengebildeter. dem nrsprnngliclien M. cncnllaris 

 niir in seinen vordersten Theile liomologer, in seinen Hanptmasse aber 

 bios initatoriscli-homodynamer oder parhomologer Mnskel."' 



