230 INTELLIGENCE IN LOWER VERTEBRATES 
waited on it for more than thirty years, it always hobbled 
with awkward alacrity toward its benefactress, while to 
strangers it was altogether inattentive.” Jesse writes of a 
young alligator which followed its master about the house 
like a dog, “scrambling up the stairs after him, and showing 
much affection and docility.” 
The formation of habits in turtles has been studied by 
Yerkes. A simple labyrinth was employed through which 
the turtle was left to find its way. Fifty trials were made, 
six or eight being given each day, and the time recorded 
which the turtle required to make its escape. The way was 
learned with a fair degree of rapidity, the time taken in 
successive trips being shortened rapidly at first and then 
more slowly. 
In other experiments turtles learned not to fall off a board 
after a number of trials. More recently habit formation 
has been studied in the turtle Chrysemis by Casteel, who 
found that the animals learn to discriminate between colors 
and to distinguish different series of parallel lines of the 
same size, but with the lines of different width. Learning 
was slow, since on the average “183 trials were necessary to 
establish discrimination.” As in the frog what was ac- 
quired was not soon forgotten; one specimen showed “ per- 
fect memory” for a line pattern two weeks after it had 
been learned. 
In general it may be said that the intelligence of reptiles 
is on a higher level than in fishes and amphibians. The 
subject is one upon which we have little well established 
information, and it affords an interesting field for future 
investigation. 
BIBLIOGRAPHY 
Bateson, W. On the Sense Organs and Perceptions of Fishes. 
Jour. Mar. Biol. Ass. United Kingdom, 1, 225, ’87. 
