THE FUNCTION OF REISSNER’S FIBER 149 
record given below, they never appeared at all. The explanation 
of these apparent exceptions must be deferred until after the 
account of the microscopical examination of the experimental 
material. 
The duration of the reaction also varied considerably, persist- 
ing in some cases for a few hours only, while in others it endured 
for several days. In a few cases it appeared to be intermittent. 
Vv. A SUMMARY OF THE RECORD OF THE EXPERIMENTS AND AN 
ACCOUNT OF THE EFFECTS UPON REISSNER’S FIBER 
A. Scyllium canicula 
2. The experimental incision was made at noon on July 7, 1910. 
The specimen quickly recovered and, although somewhat sluggish, 
appeared to swim normally. At rest, its body was bent slightly but 
otherwise the posture seemed normal. No change was observed 
until July 11, when the ventral border of the caudal fin was seen to 
be lifted slightly (about half an inch) from the tank floor. The ani- 
mal became more sluggish and, if disturbed, soon returned to rest, 
exhibiting an apparent preference for the darkest corner of its tank, 
which rendered observation more difficult. The tail rested, more- 
over, against a sloping part of the tank where wall and floor met. 
It was impossible, therefore, to be sure whether the tail was really 
slightly lifted by muscular effort or merely upraised on account of the 
elevation of its support. The whole body, however, was seen to be 
considerably curved. On July 13 and 14 the fish was more restless 
and upon the 15th, when seen at rest, the long axis of the body was dis- 
posed in a straight line (for the first time since July 8). During the 
following day it was noticed that the body of the fish was once more 
bent from side to side in long wavy curves, but with the tail, as be- 
fore, supported upon the sloping part of the tank. Next day, however, 
it was found resting well away from the back of the tank and the tail 
was uplifted, a clear two inches, from the floor. By midday on the 
18th this reaction was still more marked and the hinder part of the 
trunk and tail were bent sharply to one side. Throughout the two 
succeeding days this reaction was pronounced. On July 21 the fish 
had reverted to an earlier posture, with the tail supported against 
the sloping part of the floor, but by midday it was once again well 
out in the tank with the tail held well off the floor. On the next day 
the reaction was less marked though the body was still bent. During 
July 23 the reaction was scarcely discernible and later in the day, when 
it was decided to kill the specimen, the fish appeared normal. It 
showed very marked activity in its attempts to avoid the net, swimming 
with a wriggling movement (the head and forepart of the body being 
twisted quickly from side to side). This action in swimming had been 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 27, NO. 2 
