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THE ZOOLOGIST 



the Frog.* A male Palmate, in trials 16, 17, 18, entered r, and 

 in pursuance of a curious habit (somewhat similar to what 

 occurred in other labyrinths with other Newts, as I have de- 

 scribed) withdrew when about two inches in. In Nos. 18 and 19 

 it had formed another habit of turning a complete circle to the 

 right when in I, starting from a position facing the blind end. 

 Finally, in 19, an additional habit was made of returning to I 

 again, just after leaving it, when it had reached only half-way 

 down to the entrance barrier. In 20 all these useless habits 

 appeared en masse, as is indicated by the dotted line of the 



Fig. 5.-— a = entrance to b = the labyrinth under water ; I = cul de sac ; 

 r = passage leading to c = slope from water up to vivarium ; x = the 

 start of Newt's route ; y = the finish. 



Newt's route. In 21 the same course was made, with the elimina- 

 tion of the r habit, although it clearly hesitated, and made as if 

 to turn, but went on. 



In the same labyrinth I obtained a good instance of the 

 struggle for existence of two distinct habits. A strong I, r habit 

 had been formed, in which the Newt climbed up in the I box at 

 a certain spot on its right side, so that, by climbing and moving 



* Yerkes, E. M. : ' Harvard Psychological Studies,' vol. i. 



