266 



F. H. EDGEWORTH. 



These plienomena aiford an explanation of the innervation 

 of the palatal muscles by the Xlth medullary. 



Muscles Derived prom Trunk-Myotomes Passing to the 

 Upper Ends of the Branchial Bars. 



Vetter described a subspinalis and interarcuales muscles in 

 Text-fig. 74. 



iw..ojox, ox. 



74. 



Gallus, embryo 42 days, transverse section. 



Selachii. Furbringer subsequently showed tliat the sub- 

 spinalis and upper interarcuales (which he re-uamed " inter- 

 basales "), were innervated by the spino-occipital nerves, and 

 he classed them together as ''epibranchial spinal muscles." 

 The lower interarcuales (second and third interarcuales of 

 Vetter), he called " arcuales dorsales." 



Observation of the development of these muscles confirms 

 Fiirbringer's theory of their nature. The subspinalis and 

 ' Beevor and Horsley. 



