1032 



Anatomy. — "The Arramjemcnt of iJie motor roots mid 7i,?icln in 

 the hniln of Acipenser ruthenus diul Lepidosteus osseus.'^ By 

 F. Theunissen. (Communicated by Prof. Ij. Bolk). 



(Communicated in the meeting of February 28, 1914). 



Ill the Folia Neurobiologica of 1912 Droogleever Fortuyn ^) described 

 the iirningement of the motor roots and nuclei in rhe brain of an 

 osseous Ganoid: Amia calva. 



He came to the conclusion that Amia in many respects resembled 

 the Selachian type, though few points of analogy with the Teleosts 

 were found. 



Of the other Ganoids as yet no adequate description exists as 

 far as concerns the motor roots and nuclei. Valuable descriptions 

 of the nervous system of Ganoids are given by Goronowitsch ') and 

 Johnston ^) (Acipenser), Kingsbury ') and Ariëns Kappers '") (Amia 

 calva and Lepido.steus), but these articles contain rather a ceneral 

 account of the brain, the papers of Johnston and Kingsbury more 

 specially of the sensory systems. 



The Institute for Brainresearch possesses a complete series of the 

 brain of Acipenser ruthenus, which has enabled me to study the 

 relations of the motor system of this animal and to compare my 

 results with those obtained by Droogleever Fortuyn in Amia Calva. 



We are greatly indebted to Prof. Minor in Moskow for oui* 

 material of Acipenser ruthenus. 



The results of my researches mapped out topograi)liically after 

 Kappers's method exhibit a striking resemblance with tiiose obtained 

 by Droogleever Fortuyn, and provide a new argument for classifying 

 Amia with the Ganoids. 



My series, stained after Weigert-Pal with a contra-stain of para- 

 carmine and alternaling vv'ith a van Gieson series, enabled me to 



1) Droogleever Fortuyn, Notiz iiber den Einlritt der motorischen Nerven- 

 wurzeln in die Medulla Oblongata und iiber die Lage der motoiischen Kerne bei 

 Amia Calva, L. Folia Neurobiol. Bnd. VI, S. 27. 



2) Goronowitsch Das Gehirn und die Cranialnerven von Acipenser ruthenus. 

 Morphologisches Jahrbuch. Bnd. 13, 1888. 



3) Johnston, The Brain of Acipenser. G. Fischer, Jena, 1001. 



*) Kingsbury, The structure and morphology of the Oblongata in Fishes. Journ. 

 of Comp. Neur. Vol. VII. 



5) Ariëns Kappers, Untersuchungen iiber das Gehirn der Ganoïden Amia 

 Calva und Lepidosteus osseus. Abhandl der Senck. Naturf. Gesellschaft in Frank- 

 furt a. M. Bnd. 30, 1907. 



