( 46 ) 
ramified amidst the fibres of the tecto-bulbar track. This phenomenon 
is also indicated in Fig. 3. 
These tecto-bulbar tracks, which on the whole are very distinct in 
fishes, are especially in Lophius very large in comparison with the 
above-mentioned systems which are minute there, and a large part 
of these tracks, especially of the homolateral system, terminates in 
the region of the ventral facialis-ijucleus. 
It is a well-known fact that the tecto-bulbar tracks, originating 
in the terminal region of the optic nerve, transfer optical impressions 
on the motor systems of the medulla oblongata. 
Now we may indeed take it for granted that the visual sense in 
Lophius is better developed than in many other fishes. If e. g. we 
compare the cerebrum of Lophius with that of Gadus, we see that 
the tectum opticum of Lophius is greater with respect to the other 
parts of the brain, telencephalon and cerebellum as well as the inferior 
lobes. The proportion of the tectum opticum with regard to the other 
parts of the brain is in Lophius about twice as large as in Gadus. 
Moreover, as we saw above, taste is not much developed in 
Lophius, so that the eye appears to be its principal sense. 
In order to determine how these optical reflexes can affect the 
facialis-system in Lophius, it was in the first place necessary to know 
which muscles were innervated by the motor facialis. They proved 
to be: the musculus adductor arcus palatini, the muse, hyomandibularis, 
the muse, adductor operculi, the muse, hyohyoideus superior, viz. 
the muscle which passes into the membrana branchiostega, and two 
muscles which are difficult to distinguish from each other, the musculi 
geniohyoideus et hyohyoideus inferior. 
In most fishes the facialis also innervates the muse, levator operculi, 
but here, by way of exception, the vagus does so. 
Since Lophius, as we know, has a comparatively huge head, and 
a body, which tapers immediately behind it and ends in a tail, all 
facial muscles are comparatively much larger than in other fishes. 
This holds good particularly for the membrana branchiostega or 
the muse, hyohyoideus superior, which in Lophius appeared to be 
relatively about four times as large as in a fish with normal propor- 
tions, for which again Gadus was taken. 
When the strongly developed facial muscles contract, they close the 
gill-cavity and help to open the mouth, and now the connection 
between visual impressions and contraction of the facial muscles 
becomes obvious. 
For Lophius does not swim about, but generally lies half buried 
in the sand, so that only the dorsal part of its head and bach, 
