MORPHOLOGY OF CRANIAL MUSCLKS IN SOMK VER'L'EBHATES. 229 



Text-fig. 55. 



dLtf».60-Laxu 



If^Ait^M 



giU.nvAn,. 



Text-figs. 55 and 56.— Necturus, embryo 14A mm., transverse 

 sections. Text-fig. 55 tlirougli the layoid segment, Text-fig. 5t> 

 through the fourth branchial segment. 



