103(3 



reticular cells. Whether these cells are connecfed with secondary 

 neurones of the desc. V is dit'licnlt to tell. It seems as if several of 

 their dendrites reach into the region of the sensory V. 



It may he remembered that also van Hr)KVKLL found a large 

 qnantity of reticular cells in the trigeminal and praetrigeminal region 

 in the classes of vertebrates which he examined. 



The VII root of Acipenser enters the bulb directly behind the 

 molor V nucleus. After having reached Ihe tloor of the fourth 

 ventricle it |)ursues its course in a median direction and successively 

 shifts onto Ihe lateral top of the fasciculus longitudinalis dorsalis, as 

 is also the case in sharks, Teleosls and several Repfilia. 



Where the motor VII root makes its caudal curve, that is in the 

 region of the VIII, a group of large reticular cells is found next 

 and under the fasciculus longitudinalis posterioi-, corresponding to 

 VAN Höevkll's nucleus reticularis niedius. 



The whole VII nucleus is continuous with the IX and X, with 

 which it forms the |)OSterior visceral column, as also occurs in 

 Amia and in Selachii. A partial (Cyprinoïdae, Plenronectidae) or 

 total (Lophiiis) isolation of the VII nucleus from the posterior 

 viscero-motor column as is f\)un(i in Teleosts does not occur in 

 Acipenser. 



The posterior viscero-motor colinnn has a dorsal position and 

 extends a good distance caudad beyond the frontal limit of the spino- 

 occipital column. It i-eaches farther caudad than in Amia, although 

 neither hei-e nor there a muse, trapezius is developed (Fürbkinger)'). 

 Consequently we may not consider the caudal i)art of this nucleus 

 as nucleus accessorius as is the case in sharks. 



More vent rally and more medially — near the ventrolateral border 

 of the fascictdus longitudinalis posterior in and frontally from the 

 region of the facialis nucleus the abducens-nucleus is found, 

 which has three rootlets, which leave the brain between the VII and 

 IX root. Just as in Amia the nucleus does not lie so ventrally as 

 in Teleosts, nor is there a division into two chief groups as is fairly 

 constant in bony tishes. The nucleus does not however lie as dorsally 

 as in sharks. 



The glosso|)haryngeus niu'leus is continuous with the VII nucleus 

 frontad and the X nucleus caudad. All its cells remain near the 

 ventricle. The vagus nucleus has no special characteristics and resem- 

 bles in every respect the nucleus of the IX. The spino-occipital 

 column is the direct continuation of the motor column of the spinal 



1) Vergleichende Anatomie der Wirbeltiere mil Beriicksichtigung der Wirbellosen. 



