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upwards united between the roots of cervical nerves, does not occur in 
Camelidae, and says of this that it is “un fait anatomique de haute 
importance’. I have, however, proved that a spinal nucleus acces- 
sorius does really occur in these animals. It must a priori be con- 
sidered as extremely doubtful that an anatomical centre which 
occurs so constantly in mammals should be absent in these animals. 
Undoubtedly it is highly remarkable that the spinal accessorius fibres 
are not united in these animals to one stem but physiologically this 
cannot be regarded as a fact of “haute importance”, since also in 
these animals spinal accessorius fibres reach their destination, though 
more directly with cervical nerves, and not by a detour. 
In all anatomical text-books the nervus accessorii Willisii will be 
found described as consisting of two parts, a spinal and a bulbar 
part, the latter (because it unites wholly or partly with the nervus 
vagus) being called also the nervus accessorius vagi. The distinction 
is based on the fact that in man the accessorius spinalis and 
accessorius vagi unite into one stem, viz. the nervus accessorius 
communis, after which the bulbar part separates again to join the 
vagus after this nerve has passed the jugular ganglion. Ramon Y 
CasAL says meanwhile in his “Histologie du systeme nerveux de 
Phomme et des vertebrés” (Vol. I, p. 719) that he shares the 
opinion of Kosaka that this division into an accessorius spinalis and 
bulbaris has no significance, since they are convinced that a bulbar 
accessorius does not exist, but that the latter originates in the dorsal 
motory vagus nucleus and thus contains ordinary vagus fibres. 
Ido not agree with CayaL and Kosaka, though their view seems 
to be proved by the fact that in domestic animals the two parts of 
the nervus accessorius do not unite into one stem, e.g. in the horse 
the front part of the pars bulbaris enters the ganglion jugulare, 
while only the hindmost part joins the accessorius spinalis; in 
ruminants and carnivora, on the other hand, the entire accessorius 
bulbaris enters the ganglion jugulare, while in the pig this part 
reaches the nervus vagus late, viz. at the place where the ramus 
pharyngeus is given off. On account of my observations, however, 
in the camel and in the Jama, I have come to the conclusion that 
accessorius cells really do occur in the oblongata. In these animals 
the accessorius nucleus is very distinct in the region of the dorsal 
motor vagus nucleus; in the lama it immediately joins the aforesaid 
vagus nucleus, in the camel there are only traces of such a connection. 
In any case, in both animals the accessorius nucleus extends into 
the oblongata. I am willing to assume that in the so called ramus 
internus n. accessorii, i.e. in such part of it as joins the nervus 
