320 Journal of Compakative Nkurology. 



vesicle, so is the ganglion of the glosso-pharyngeus in close 

 contact with its caudo-ventral wall, and has fused with the 

 portion of its cells which I have mentioned and drawn as 

 the sickle-shaped investment of this part of the wall of the 

 vesicle.(') This cell-girdle, up to the time of the exit of 

 the embryo is continuous with the mass of the principal 

 ganglion of the facial, and I have accordingly assigned it to 

 the latter. But it changes later. In larvje of 4 mm. the 

 separation is completed, and the cell group under considera- 

 tion has by this time connected itself with the glosso- 

 pharyngeus. It thus comes to pass that the continuous cell 

 mass, which originates from the epidermis in closest contact 

 with the labyrinth pit and is further augmented by the cells 

 of the wall of the latter, embraces the lateral portions of two 

 ganglia, the larger fore part going over to the principal gan- 

 glion of the facial and the smaller hind part to the ganglion 

 of the glosso-pharyngeus. Along with this the glosso- 

 pharyngeus moves out of the particular place which I believe 

 must be assigned to it originally, before the separation of the 

 ganglion mass adjoining the labyrinth vesicle into two parts 

 has been completed. 



As the glosso-pharyngeus is now, it consists of a stout 

 fibrillar root, which is evidently separated from the acusticus 

 but unites with the.vagus root lying caudad. The root enters 

 an elongated ganglion whose medial part, likewise present 

 from the first, has united secondarily with the lateral part 

 which was joined to the labyrinth vesicle. This principal 

 ganglion, extending further, now fuses with the epibranchial 

 cord, so that it completely takes in the sixth epibranchial 

 ganglion. At the same time, however, it connects itself, by 

 a tract (Zug) directed cephalad, with the fifth epibranchial 

 ganglion. The latter is thereby closely related both to the 

 facialis and to the glosso-pharyngeus. 



The relations of the vagus, in the strict sense, when 



I Arch. f. Mikr. Anat., i8qo, p. 524, Figs. 54, 74. 



