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 hi 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 hi 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. 



