MORPHOLOGY OF CBAXIAL MUSCLES IN SOME VERTEBRATES. 299 



Taking part in the 

 formation of hypo- 

 branchial spinal 

 muscles. 



1st, 2nd. 



2nd (few cells), 

 3rd, 4tli, 5th 

 (Miss Piatt). 



2nd, 3rd, 4th 

 (Agar). 



2nd, 3rd, 4th 

 (Agar). 



1st, 2nd, 3rd. 



2nd, 3rd, 4th, 5th 

 (Hoffman) 



1st (few cells), 

 2nd, 3rd, 4th, 5th, 



2nd, 3rd, 4th. 



2nd, 3rd, 4th 



(Harrison). 



2nd, 3rd, 4th. 

 2nd, 3rd, 4th. 



4th, 5th, 6th, 7th 



8th (Neal). 

 4th, 5th, 6th, 7th. 

 : Sth. 



to be developed, or after development to atrophy, and that 

 this takes place from before backwards. The non-develop- 

 ment or atrophy affects dorsal more readily than ventral 

 roots. Reduction, i.e. atrophy after development, o£ somites 



