552 Stewart Paton 



all the seetions in which the Trigeminus gauglion appears. The fibrils 

 entering the i)eri})bei'y to form this nerve lie in the same plane as 

 does tlie up[)er portion oftheFacial ganglion. Both the Trigeminus 

 and Acustico-facial ganglia uow coutain countless fibrils. The eoii- 

 uections with the ventro-lateral group of cells in l)oth iustanees 

 have, as compared with the earlier stages, been greatly re-enforced. 

 In the Facial nuclei, more markedly than in the case of the Trige- 

 minus, the diflferentiation of both cells and fibrils has extcnded in- 

 wards from the periphery towards the central canal, and many of 

 these Clements are surrounded by a diffuse neuroreticulum. Begiu- 

 uing with the more caudally situated portions of the medullary centre of 

 the Trigeminus the number of neurofibrils appearing in the dorsal part 

 of the medulla, as well as those friuging the whole of the outer 

 border of the lateral zone increases rapidly, while the neurofibrilla- 

 tion taking place about two groups of cells in the marginal veli 

 zone, dorsal to the prominent ventro- lateral group, has already 

 become a prominent characterisfic of sections through this area. 

 Both the Eamus mandibularis as well as Ramus maxillaris are very 

 well supplied with fibrils. In euch of these uerves, although the 

 neurofibrils raay readily be fouud in contnct with the inner epithelial 

 layer, they do not seem to penetrate it at this stage. Thick bund- 

 les of fibrils enter the Acustico-facial ganglion from all the lateral 

 parts of the medulla. Those comiug from the extreme ventral or 

 dorsal areas beud sharply at their point of exit as they pass into 

 the gauglionic mass. 



The Buccal brauch of the Facial may be seen in elose contact 

 with the medulla sending off many fibrils which creep in between 

 the e[)idermal nuclei, sometimes endiug abriiptly just before they 

 reai;h the most externa! layer of cells, Avhile others in the de e}) er 

 layers frequently unite to form a definite network. The Raums 

 hyoideus with its two bran -hcs post- and praetrematicus is easily 

 recoguizable, its neurofibrils at this period stili seem to end quite 

 free in the mesenchyme. The Acustic brauch from the ganglion has 

 already attained considerable proportions and tìlamcnts from it may 

 already be detected penetrating the wall of the ear. The manncr 

 in which these auditory fibrils end does not difter in any particular 

 from that observod in connection with the terrainations in the epi- 

 dermis of the other nervcs already describcd. 1 have not been 

 able to satisfy myself that the Ramus posttrematicus is, as Guthke 

 affirms, so free from nuclei as to make this condition more or less of a 



