( 30 ) 



position in selaciiii, is tlie situation on tiie border of the ventricle 

 cavity on, or rather in, its ependyma; in scyllium especially on 



Vmos. 



V 11 U'S. 



Lophius piscatorins. 



sagittal sections one can see the cells bulging out the ependyma 

 iayei' belbi'c them, whereby they almost seem to hang in the cavity 



Dpchss. IV 



Fig. 3. Scyllium canicula. 



(fig. 3). In this last figure an idea is likewise obtained of the fron to- 

 caudal dimensions of the nucleus on a section situated not far from 

 the medial line. 



The study of a series of cross sections shows that the most frontal 

 cells occur in the anterior part of the tectum opticum, and that the 

 most caudal ones are met with in the \'elum medullare anticum 

 frontally to the level of the trochlear nucleus. The compact nucleus of 

 the teleostei, on the other hand, extends over no greater sagittal 

 distance than about 250 f(. iJopJiius). As regards the division of the 



