15 
The anterior ones of the post-branchial myotomes, from: 
the ninth (seventh post-otic) onwards (NEAL, 1897, p. 444, 
KOLTZOFF, 1902, p. 304), produce myotomic buds which 
grow out behind and under the gill slits and produce the- 
NS 
IRAASS 
S8 TEN A, 
EN 
a IT fe 
ET BENEN 
'e d 
Fig. 29. Head of Fetromyzon fluviatilis, dissected, 
aiter GOOJRICH, 1909, p. 40. 
1, Il, eye-muscles derived from the two 
prc-otic somites. 
Ul. IV, V, etc. myotomes. 
occ. a. occipital arch. 
hypobranchial musculature which afterwards exhibits a 
secondary segmentation corresponding to the situation of- 
the gill-slits. It is innervated by ventral roots of the myo-- 
