64 
As shown also by HATSCHEK's instructive figure of the 
head of Amphioxus, reproduced here as fig. 26, there is a 
dorsal spinal nerve between every two myotoms. It belongs 
ni, gr 
nad 
3 
en ese: 
EEE 
et 
eg: 
ba oeh En kad 
de Ei 
Fig. 26. Head of Amphioxus, from the left side, after HAT SCHEK 
1892, p. 143 (nomenclature altered). 
A,B,C, etc. segmental nerves belonging to segments I, II, II, etc. 
a, anterior branch of the first segmental nerve (“N. opkfhal- 
micus profundus”), Ch. notochord, cu, prof, SUp- branches 
of the segmental nerves, fl. rest of the neuropore, : 
nervus recurrens to the branchial plexus, fr. Pr. } rostral 
prolongation of the first somite, S. HATSCHEK's groove, T. 
tentacles (cirri), Vel. velum, I, II, III etc. myotomes. 
