TIONS 



ph.X.l-4, first to fourth ramus pharyngeus 

 X. 



prt.IX, ramus pretrematicus IX. 



prt.Xl-4, first to fourth ramus pretrema- 

 ticus X. 



pst.IX, ramus posttrematicus IX. 



pst.Xl-4, first to fourth ramus posttrema- 

 ticus X. 



sp.1-6, first to sixth spinal nerves. 



spt.IX, ramus supratemporalis IX. 



spt X, ramus supratemporalis X. 



to br.pl, to brachial plexus. 





trap, nerve to trapezius muscle. 

 tr.hmd.VII, truncus hyomandibularis VII. 

 tr.io. V + VII, truncus infra-orbitalis V + 



tr.so. V+VII, truncus supra-orbitalis V + 



VI, nervus abducens. 



VIII, nervus acusticus. 



VII r.ll, lateral line roots of facialis. 



visc.X, ramus visceralis (intestinalis) X. 



vpo, nerve to ventral pit organs. 



X r, roots of vagus. 



tJ he UtU " es , f th \ n fe, eye, spiracle and the five gill clefts are indicated by 

 the conventional symbols printed above the figure. 



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