270 



C. U. Aricns Kappers 



In studying the central nervous system of the cod, in 1901 for my in- 

 augural dissertation, I was struck by the singular position held in this ani- 

 mal by the niideiis abdiccens (fig. l). 



Instead of finding this nucleus in a dorsal position in the neighbour- 

 hood of the floor of the ventricle not far from the fasciculus longitudina- 



ant. 



Crll.b.V. 



Fig. 2. — ^'entral position of Ihe abducens nucleus in Mugil ehelo, after v. d. Horst 



lis posterior, as is known to be the case with man and all mammals (fig. 3 

 and 7), I found this nucleus in cods, divided in two parts, both occupying 

 an extremely ventral position not far from the base of the oblongata. 

 My further researches and those made by others, especially by Tello, 

 van der Horst and by Davidson Black on bony-fishes, prove this phe- 

 nomenon to be almost constant with these animáis (fig. 2). 



