( 45 ) 
W 'Now, are there sufficient reasons to take for granted, that the 
I removal of the motor facialis-nucleus in Lophius is likewise a case 
of neurobio taxis ? 
- In order to answer this question it should in the first place be 
settled towards which track the facialis-nucleus is shifted and next 
= it should be explained why exactly this track in Lophius conducts 
|§ Stronger stimuli than in many other fishes. 
| Three tracks, which have a more or less ventral situation, may 
be considered to cause the shifting of the facialis-nucleus. These are 
the tractus tecto-bulbaris, (Fig. 1, tr. t.-b.), the radix descendens 
| trigemini (Fig. 1, r. d. trig.) and the secondary gustatory tracks 
(sec. g. tr.) with the reticular substance surrounding them and the 
llobobulbar tracks. Dendrites of the motor facialis-cells have been 
traced in the areal of all these tracks. 
Now apart from the fact that the shifting is more towards the 
i tractus tecto-bulbaris than towards the two other tracks, still better 
arguments may be advanced why the secondary gustatory tracks and 
the radix descendens trigemini are not the cause. 
| Suppose the radix trigemini to draw the facialis-nucleus in a basal 
direction, then we should expect the trigeminus-nucleus itself to be 
still more strongly influenced. Now this is by no means the case in 
Lophius. And if we look at Gadus, an animal where, as appears 
also from Figs. 1 and 2, the radix descendens trigemini is about 
three times as thick as in Lophius, compared with the thickness of 
the oblongata, we see that there the facialis-nucleus is still partly 
situated close against the ventricle, partly shows a slight depression 
(Fig. 2), though not nearly so much as in Lophius. 
Therefore it cannot be attributed to. the radix descendens trigemini, 
that the facialis-nucleus in Lophius lies more ventrally. 
I’he secondary gustatory tracks, which, owing to their position, 
might be the cause of the nuclear shifting, are but very slightly 
developed in Lophius. In Tinea, the tench, on the other hand, very 
large gustatory tracks are met with (Fig. 3, sec. g. tr.) and yet the 
facialis-nucleus, though situated not quite dorsally, is by no means 
so far displaced as in Lophius. The secondary gustatory tracks can 
i therefore hardly be considered as the cause of the greater displace¬ 
ment in Lophius. The same holds good for the lobo-bulbar tracks 
because they are much smaller in Lophius than in Gadus and Tinea. 
Preparations from Tinea strengthened the supposition that the 
tecto-bulbar track was the point of attraction for the facialis-nucleus 
as also here it was clearly to be seen that numerous protoplasm- 
offshoots of the ganglion-cells (dendrites) of the facialis-nucleus were 
