sexes formed the maze habit considerably more rapidly than the 

 300 day animals. 



The fact that in the number of trials, total time and 

 total distance required to learn the problem, the males at 65 

 days are superior to those at 25 days while the reverse is true 

 of the females, sugp;ests the possibility that the capacity for 

 habit formation develops earlier in the females than in the 

 males. 



Day and Iflght Work. 



It has been stated by Slonaker and is generally believed 

 that the albino rat is nocturnal. With a view to testing this 

 matter certain rats in the twenty-five and two hundred day groups 

 were run always in the day time, certain others always at night. 

 The averages for the day and night rats were obtained in the 

 same manner as the group averages, from Tables A and C. 



The twenty-five day rats run during the day were numbers 

 1,2,4,5,6,15,16,17,19,20,21 and 24, seven of which were males 

 and six females. Those run at night were numbers 8,9,10,11,12, 

 13 and 14, two males and five females. The averages which ap- 

 pear below in Table 1 seem to show the day rats slightly super- 

 ior in distance and trials while the night rats consumed less 

 time and had a slightly higher final efficieiicy. These differ- 

 ences are negligible, and there may be said to be no difference 

 in learning at this age between the rats run in the day time 

 and those run at night. 



The day grouj of two hundred day rats consisted of two 



