669 



a nucleus accessor! spinalis and no nervus accessor! us spinalis. (This 

 observation of Lesbke's has been confirmed by Professor Winoate 

 Todd of Cleveland in a letter directed to Dr. C. U. Ariëns Kappers). 

 A more difficult question is presented in this respect by the dorsal 

 motor vagus nucleus itself. In the lower vertebrates numbers of 

 cells leave the spinal portion of the nucleus out of the connection 

 into a more ventral level ; in the Alligator a part of the dorsal 

 motor vagus nucleus is even attached to the frontal horn grey matter, 

 and in birds to the tongue nucleus, which here forms the direct 

 continuation of this grey matter (Kappers). In mammals the rise of 

 the vagus and hypoglossus cells in the hypoglossus region between 

 the two nuclei is a common phenomenon, which undeniably is as 

 clearly seen in the giraffe as anywhere. Spinally from the nucleus 

 XII,, however, it was apparent in many sections in the giraffe 

 series, that these ventral cells form one whole with a series of frontal 

 horn cells of small type, often an arched series of cells were even 

 noticeable, which began dee[) in the frontal horn and ended dorsaliy 

 from the central canal ; the same was frequently observed in the 

 first cervical segment, i. e. spinally from the dorsal motor vagus 

 nucleus. My interest in this circuuistance increased when I met the 

 same phenomenon, though in a much stronger degree, in my series 

 of the calf foetus, where these ventral cells of the said vagus nucleus, 

 reaching deep into the motor iiorn, are of much larger type. This 

 plieuomenon was to be seen in this series, for instance, in these 

 sections where there was a connection between this vagus nucleus 

 and the XI nucleus (fig. 21). Thus in this respect also there are 

 very primitive conditions in the giraffe as in the tongue nucleus, 

 which I am unable to explain, tiie more so as I know riOthing of 

 the rise of the nervus vagus in this animal. 



CONCLUSIONS. 



1. The nervus accessorius spinalis occurs in the '!'■'• and 2'"'» cervical 

 segment in the girafie as in the other mammals, with the exce[)tion 

 of Camelidae. 



2. Spinally from the nucleus Xll. the dorsal motor vagus 

 nucleus of the giraffe appears to be at five consecutive places in 

 direct connection with nucleus XI. 



3. In the most spinal portion the dorsal motor vagus nucleus 

 of the giraffe does not occur constantly ; in front of its frontal pole, 

 there is still a small, quite separate, portion of this nucleus. 



4. Frontally from the unions of Nucl. mot. X. dorsalis and 



