647 



Anatomy. — "J7«e vagus-area in Camelopa'r dolus Giraffe". By 

 Dr. H. A. Vkrmeui.en. (Communicated by Prof. C. Winkler). 



(Goinmunicated in the meeting of September 25, 1915). 



Lksbre, in his exliaiisfive treatise: "Recherches anatomiques sur les 

 Camélidés" {Archives du Muséum d'Histoire naturelle de Lyon, \o\. 

 VIII. 1903), wrote that no nervus accessorius spinalis occurs in 

 these animals, and that the nervus laryngeus inferior does not follow 

 the usual recurrent course, but emerges together with the nervus 

 laryngeus superior from the vagus stem. Lesbre endeavoured to explain 

 the latter circumstance by expressing the supposition that the usual 

 course of the nervus recurrens would be useless by reason of the 

 unusual length of neck in the Camelidae; and he expressed the 

 desirability at the same time of the above relations being also studied 

 in the giraffe, whereby support might be found for his assumption, if 

 similar proportions were found in this extremely long-necked animal. 



On a microscopical examination of the vagus area in Camelidae, 

 I saw that the nucleus accessorii spinalis is indeed present, and 

 that especially in the caudal third portion, the nucleus ambiguns is 

 but poorly developed in these animals. I also found several remark- 

 able relations, particularly of vagus and accessorius nuclei of 

 Camelidae 'j which roused in me the desire to examine what the 

 circumstances might be in the giraffe. I was able to examine one 

 part only of the central nervous system of this class of animal, and 

 was enabled to do so by tiie courtesy of Di-. C. U. Ariëns K.\ppers. 

 Director of the Central Institute for Brain Research, at Amsterdam, 

 who kindly placed part of the material there at my disposal. This 

 consisted of the brain stem and a piece of the first cervical segment 

 of one specimen, and the first and second segments of anotlier 

 specimen. In the latter preparation the nervi accessorii Wiliisii 

 could be seen perfectly intact in their usual course between the 

 roots of the two first cervical nerves, so that in this respect the 

 giraffe differs here at least, froui the Camelidae. Of the portion 

 of cervical cord and vagus area of the former preparation about 

 2500 sections of 18 jt have been coloured with cresil violet. From 

 a part of the second preparation alternating series have been 

 made according to VVkigekt Pal and Van Gibson, while the otiier 

 part, for the fibre course, has been treated after Sheldon's method. 



The illustrations given in this paper are, with the exception of 



') H. A. Vermeulen. The vagus area in Camelidae. Kon. Acad, van Welensch, 

 at Amsterdam. Meeting of 27lh February 1915. Voh XVll. 



42 



Proceedings Royal Acad. Amsterdam. Vol. XVllI, 



