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both. Also that their neurites pass out of the dorsal roots of the 
spinal nerves. 
I cannot yet see my way clear to infer any exact homology be- 
tween the giant cells I have observed in the flat-fishes and the giant 
cells described in a more or less similar position in the adults of the 
fishes mentioned in the first part of this article. Lophius would 
present the most probable homology except that the neurites pass 
cephalad in this fish, while in the flat-fishes they pass caudad. This 
would not, in my mind, prohibit the identity of the two groups of 
cells provided their neurites passed through a dorsal nerve root in 
each case and were distributed in the same tissues and used for the 
same purpose. In Amphioxus the giant cells of the anterior por- 
tion of the cord direct their neurites caudad, while the same kind of 
cells in the posterior portion of the cord direct theirs cephalad. If it 
was possible to prove the identity of the giant cells of the flat-fishes 
with the anterior giant cells in Amphioxus and of the giant cells 
of Lophius with those in the posterior portion of the cord of 
Amphioxus a solution of the difference between the giant cell 
apparatus as found in the Heterosomata and in Lophius would 
be arrived at. 
MAUTHNER’s fibres, it may be said here, are present in the flat- 
fish and I have traced them to a crossing in the brain, after which 
they end in two large cells under the ventricle as in other forms. 
I cannot, on the other hand, yet feel sure in affirming the homo- 
logy of the flat-fishes giant cell apparatus with the transient ganglion 
cells found in the embryos of Salmo, Raja etc. And yet I feel 
that they are the same as these transient cells and will be proved 
to be the same cell when more work has been accomplished on these 
and other forms. 
Princeton University, New Jersey, U. S. A., 
December 16th, 1896. 
Addenda. 
I have lately been examining the cords of all those fishes which 
apparently possess highly specialized sense-organs in the skin of the 
fins and body. In the cord of Hemitripterus americanus, 
which is very abundantly supplied with such organs, I find the giant 
ganglion cells abundantly developed in the median dorsal fissure. 
Also in Batrachus tau, the toad fish, I find a similar appa- 
ratus with strange cells that possess an eccentric nucleus. I have 
