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into a more ventral level ; in general these more ventraily situated 

 cells are longer than those of tlic vagus type, and in this respect 

 bear more resemblance to those of the nucleus XI. (fig. 3). After the 

 dorsal motor vagus nucleus has separated from the accessorius 

 nucleus and the latter at this place has disappeared, except for 

 a few cells, the former numbers 15 — 16 cells, frequently to be seen 

 more or less clearly arranged in two rows one above the other. Rather 

 more frontally the nucleus XI manifests itself again more strongly 

 and shortly after it is clearly seen to unite with the vagus nucleus 

 in question. This time too they separate again, and the accessorius 

 nucleus disappears entirely or almost entirely, after which the dorsal 

 motor vagus nucleus appears as a loosely built group of cells, containing 

 on an average 20 cells. The \Vhole is more or less oval, with the blunt 

 pole pointing laterally. Striking is the large size of the cell type in this 

 region ; ventraily shifted cells are no longer to be seen. A few sections 

 more frontally the cell type becomes smaller again, and the nucleus 

 decreases considerably in size, containing in many sections not more 

 than 3 or 4 cells, the accessorius nucleus, however, soon appears 

 again, and the process of uniting with the vagus nucleus is gone 

 through for the third time. Now, however, the two nuclei are but 

 a short time united, and only in a few sections is the closer con- 

 nection between X and XI to be seen. Simultaneously, however, 

 vagus cells have shifted into a more ventral level. The whole 

 process, viz. the decrease in size of nucleus X dorsalis, then a union 

 with the accessorius nucleus, accompanied bj- a spreading of the 

 vagus cells into a more ventral region, takes place twice more, 

 though in lesser degree. In the giraffe the union of the dorsal motor 

 vagus nucleus with the accessorius nucleus thus successively occurs 

 at five consecutive places, (fig. 2). This takes place before anything 

 can be seen of the tongue nucleus. From this moment the dorsal 

 motor vagus nucleus occurs constantly ; it is loosely built and egg- 

 shaped, with the blunt pole pointing ventro-laterally, and contains 

 20 — 25, mostly large cells (maximal 50 (i) ; a peculiarity here is. 

 that sometimes the laterally situated cells are of a larger type than 

 those lying more medially. As in the lama and the camel, the cell 

 groups from the right and left come right to the raphe and soon 

 we see here too a commissural motor vagus nucleus appear, as I 

 have described in the lama and cainel. It appears near the spinal 

 pole of nucleus XII, is less developed than in Camelidae and not 

 constant in appearance (fig. 1. 2 and 4). 



Whenever the tongue nucleus is well developed, the dorsal 

 motor vagus nucleus becomes mucii compacter and its ventro- 



