T, ramus palatinus VII. 

 , ramus pharyngeus IX. 

 , first ramus pharyngeus X. 

 , fourth ramus pharyngeus X. 

 ", ramus pretrematicus IX. 

 , first ramus pretrematicus X. 

 '■., fourth ramus pretrematicus X. 

 , ramus posttrematicus IX. 

 , first ramus posttrematicus X. 

 ., fourth ramus posttrematicus X. 

 , first to sixth spinal nerves. 

 , ramus supratemporalis IX. 



. The outlines of the nose, eye, spiracle and the five gill clefts are indicated 

 1 by the conventional symbols printed above the figure. 



25 



spt.X, ramus supratemporalis X. 

 tr.hmd.VII, truncus hyomandibularis VII. 

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



VII. 

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



VII. 

 VI, nervus abducens. 

 VIII, nervus acusticus. 

 VII r.ll, lateral line roots of facialis. 

 risc.X, ramus visceralis (intestinalis) X. 

 X r, roots of vagus. 



