3i8 Journal oi<- Comparative Neurolo(;y. 



the hinder surface of the second principal ganglion of the 

 trigeminus. It reaches around the auditory vesicle on the 

 median and ventral sides as far as its middle, and here ends 

 in a point. The contact w^ith the wall of the auditory vesicle 

 is very close. 



I assign to the same region two ganglia of the epibranchial 

 chain, namely, those lying in front of the first and second 

 gill pouches, and which, numbered from before, would be 

 four and five. The fifth epibranchial ganglion is immediately 

 connected with the principal ganglion of the facial, and par- 

 ticipates in the composition of the N. branchialis, a massive 

 cord proceeding chiefly from the principal ganglion into the 

 hyoid arch. The diminished fore end of the principal gan- 

 glion extends into the commissure which connects the fifth 

 with the fourth epibranchial ganglion. At this stage a short 

 nerve "anlage" proceeds from the latter, which is produced 

 into the substance of the mandibular arch, superficially, in a 

 ventral direction. But this fourth epibranchial ganglion 

 occupies an intermediate position, and is connected both 

 with the principal ganglion of the facial and the second 

 principal ganglion of the trigeminus. While I assign it pro- 

 visionally to the facial region, this view needs to be proved 

 by further investigations as to its later fate. 



I have, from earlier stages, represented as acusticus the 

 hinder portion of the one continuous branchial root of this 

 region, (') which is connected with the wall of the auditory 

 vesicle at the base of the recessus labyrinthi, and has, at that 

 time, developed no ganglion. It has not essentially changed 

 from there on to the stage now under consideration. The 

 acusticus, too, only shows here this one place of connection 

 with the auditory vesicle. Although cells may be seen be- 

 tween its fibrilhe and in connection with them, they cannot 

 yet be called a ganglion. 



3. Jxcgion of ihe I 'agns Group. — As belonging to this 



I Arch. f. Mikr. Anat., 1890, Bd. 35, p. 543. 



