194 Bulletin Wisconsin Natural History Society [Vol. 13, No. 4 
is the best of all five turtles as his per cent of error for the entire 
period is only 31%. No. IV made one perfect record, and No. V 
made none. No. V seemed to be able to distinguish the sounds 
but became badly mixed in the last two or three trials and unable 
to remember, though during the last week of the experiments he 
did as well as the others. The percentages of error of the turtles 
are as follows: 
Peb Cent 
Turtle No. I July 29 to Aug. 11 50 
Turtle No. I Aug. 11 to Aug. 27 33 
Turtle No. II July 29 to Aug. 11 521 
Turtle No. II Aug. 11 to Aug. 25 23 
Turtle No. II Aug. 25 to Sept. 6 21 
Turtle No. Ill Aug. 10 to Aug. 23 33c 
Turtle No. Ill Aug. 23 to Sept. 6 281 
Turtle No. IV Aug. 8 to Aug. 21 45 
Turtle No. IV Aug. 21 to Sept. 6 26 
Turtle No. V Aug. 15 to Aug. 28 42 
Turtle No. V Aug. 28 to Sept. 6 27 
From the observations made during the experiments I believe 
that the mind of the turtle is erratic. One day of almost com- 
plete success will be followed by one of almost total failure. I 
do not think this is due to inability to discriminate between the 
two sounds, but to the inability of the turtle to fix his attention 
on more than one thing at a time. When he sees the food, his 
mind is fixed on how to get possession of that food, regardless of 
all else. The greatest difficulty in this experiment was to train 
the turtle to focus his attention on the sound of the bell or whistle, 
as well as on the food. Even after the third week of the experi- 
ments he w r ould pay no attention to the sounds until he had been 
shocked at least once. 
Toward the end of the experiments three days, September 2 
to 5, were allowed to elapse during which the turtles were not fed. 
All five did as well, or nearly so, afterwards as they had done the 
week before; thus showing that they could remember for this 
period of time. Later two weeks were allowed to elapse. All five 
seemed to have forgotten the significance of the sounds completely. 
No. Ill remembered to come up on the zinc plate to be fed, but 
paid no attention to the sound of the whistle or the bell. This, 
however, may have been due in a large degree to the fact that the 
