8b3 



pharyngeal ganglion. It fuses with this epiblast just on the level of 

 the uotochord. At this point of fusion the epiblast has previously- 

 undergone changes and forms a special neuroepithelium composed of long 

 cylindrical cells. The initial thickening" I have previously called the 

 primitive branchial sense organ. Although it does not remain in the 

 condition of a single sense organ there can be little doubt that such 

 was once the case, but it would take up too much space to discuss the 

 matter here. 



When the ganglionic Anlage has fused at one point of its course 

 with this neuroepithelium, a proliferation of cells into the Anlage en- 

 sues. This gives rise to the lateral ganglion mentioned above. It 

 fuses with the neural ganglion, and the complex ganglion thus formed 

 begins to leave the skin. For the phenomena which follow this I refer 

 the reader to ray paper on the branchial sense organs. 



Here only the remark that against Profs. Dohkn, Froriep and 

 others I can maintain my position that all the nerves to the lateral 

 or branchial sense organs are differentiations of the neuroepithelium. 

 The neuroepithelium grows in length in one or more directions — je 

 nachdem — and from its growth are formed both sense organs and 

 their nerve in every case. The homologue of the chorda tympani in 

 Sharks which Dohrn and Froriep consider to be a good instance of 

 a nerve of lateral or branchial sense organs which does not arise is 

 this way , appears to me, on the contrary, to be a nerve for 

 which the development from neuroepithelium is especially easy of de- 

 monstration. 



For a fuller discussion of the problems presented by the deve- 

 lopment of a cranial ganglion, I refer the reader to the various parts 

 of my researches in course of publication. The question of the for- 

 mation of the root of a cranial ganglion now arises, and regarding 

 this I will here only insist that a great number of cells of the ganglion 

 are used in forming the nerve root. 



Since I published my observations nearly three years ago, no 

 new results have been obtained as to the beginnings of the ganglia 

 in this group. At the recent Würzburg Congress Prof. Rabl 

 declared that his researches led him to confirm Balfour's con- 

 clusions that the ganglia are direct outgrowths of the central ner- 

 vous system. If Prof. Rabl will look at his preparations again 

 after the appearance of Part I of my researches, he may possibly 

 arrive at quite different conclusions. — I say may, because much 

 depends on the preparations, for many of the appearances I have 

 described could hardly be made out, or only with difficulty in the 



