654 



it reappears as a small cell-group which is seen for about 40 sections 

 and then disappears definitively. 



Nucleus ainhiguus. In general the arabiguus is well developed 

 in the giraffe. In the most spinal portion alone, it is small, contains 

 8 — 12 cells only. On this level I have been able to show repeat- 

 edly and more distinctly than was the case in the camel and 

 the lama, the simultaneous presence of the nucleus dorsalis vagi, 

 the nucleus accessorii and the ambiguus. Near the spinal pole 

 of the tongue nucleus, however, the arabiguus of the giraffe 

 has often grown to a powerful nucleus which, though varying in size, 

 is seen to be constant in numerous sections. In the strongest 

 development at this place we see a loosely built nucleus of about 

 45 large cells, all arranged in a ventro-lateral direction (fig. 9). 

 Frequently the ventro-lateral part is noticeably more developed than 

 the rest. This portion soon grows out medially in a nearly horizontal 



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Fig. 9. Fig. 10. 



direction with a particularly large cell-type, till the whole has moi-e 

 or less the form of an equilateral triangle, with the fewest cells in 

 the centre and at the medial side (fig. 10). Sometimes in successive 

 sections we see mainly the basis of the triangle, so that the nucleus 

 then appears as a horizontal column consisting of extremely large 

 cells. In circa 300 successive sections the ambiguus in this region 

 is clearly visible in the form described above, after which it varies 

 very much, sometimes being altogether absent : in the most places, 

 however, it is present in \'arious forms, though less well developed 

 than before ; we can distinguish two separate cell groups, a medio 

 dorsal and a ventro-lateral (nucleus laryngeus and nucleus cardiacus 

 of KosAKA and Yagita) or only the ventro-lateral part of it, sometimes 

 attached to these we see scattered cells which impart to the whole 

 a sort of form of a triangle in which the nucleus is seen more 

 spinally. We now see it growing gradually till it gets near the calamus, 



