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present recognize it that the Anlagen arc sometimes regarded as a 

 continuous structure. In many cases I have however convinced myself 

 that thes pinal ganglia- Anlagen are segmental from the start. 



After the neural tube separates from the epiblast it is also in 

 nearly all my preparations sharply defined from the developing gan- 

 glionic Anlage, and I can agree with no observer who regards the 

 latter as an outgrowth from the former. 



At the same time that a portion of the „Anlage" is growing to- 

 wards the epiblast the proximal part is gradually slipping down the 

 side of the brain, and finally this gets into the position in which its 

 permanent — and only — roots of attachment to the brain are 

 formed. 



The mode of formation of the roots of the nerve may be post- 

 poned for consideration with the description of Elasmobranch deve- 

 lopment. 



The processes described for the ganglionic „Anlage" of the mid- 

 brain region, which gives rise to the mesocephalic ganglion and the 

 homologue of the ophthalmicus profundus are essentially the same for 

 the trigeminus, facial, auditory, glossopharyngeal and vagus ganglia, 

 and probably, though as yet I have had no opportunity of examin- 

 ing this point very fully in the Chick, for the olfactory nerve and 

 ganglion also. 



In the Lizard and Shark, let me say, I have shewn such a de- 

 velopment for the olfactory nerve and, with apologies to Prof. Gegen- 

 BAUR, its ganglion also. — This study is also now in the press. 



My account thus far agrees in the main with Onodi's for the cra- 

 nial ganglia of the Chick. But I cannot find in his paper anything 

 to show that he holds the absence of connection between brain and 

 ganglionic Anlage on which I lay so much stress, and, judging from 

 his statements of the development in Selachians, I incline to the con- 

 clusion that he really considers the two things to be continuous. With- 

 out figures^), — and as I mentioned before, Onodi gives none, — it 

 is impossible to be certain of his views on this point. The sub- 

 sequent stages of the cranial ganglia in the Chick bear a relation to the 

 rudiments of the branchial sense organs, or lateral sense organs, whose 

 presence in the Chick I recorded nearly three years ago. In the Chick 

 Dr. Kastschenko has recently „rediscovered" them. The „Anlage" — I 

 refrain now from calling it a nerve for reasons to be afterwards 



1) The three parts of my own work will be illustrated by something 

 like 12 plates. 



