14 



D. B. CASTEEL 



TABLE 5 



Turtle No. 13, Black and White 

 Discrimination 



Result of preference trials: Black 16, 

 white 24. Fed in black box 



Test Right Wrong 



1 7 3 



2 4 6 



3 3 7 



4 6 4 



5 5 5 



6 3 7 



7 6 4 



8 5 5 



9 6 4 



10 3 7 



11 4 6 



12 6 4 



13 4 6 



14 6 4 



15 5 5 



16 7 3 



17 6 4 



18 7 3 



19 6 4 



20 7 3 



21 6 4 



22 4 6 



116 104 



used in any of the experiments described. It was a large, slowly- 

 moving, rather sulky animal, extremely difficult to tame and 

 apparently in need of but little food. It early developed a 

 habit of right turning, and at no time during its 220 trials 

 showed consistent improvement. As compared with sofhe 

 others, notably No. 10, it illustrates well the marked difference 

 in behavior which different turtles may show. Its record is 

 given in table 5. 



PATTERN DISCRIMINATION 



As the sequel will show the above heading shoiild rather 

 read lack of pattern discrimination. The patterns used, reduced 

 one-half in size, are shown in Fig. III. Their areas are equal. 

 It may well be argued that the choice of patterns was unfor- 

 tunate and that designs more markedly different should have 

 been used. The history of but two turtles will be given here. 

 Several others were tried but through seeming lack of ability 



