MOVEMENTS, ETC., OP FRESH-WATER PLANARIANS. 591 



specimens gave the usual positive or negative reaction, or 

 kept their course without change, showing only the local con- 

 traction. The first series which I will report was on an 

 individual which was in a condition of great excitation, 

 moving about with more than normal rapidity, and generally 

 '' stirred up." The results of twenty-three stimulations on 

 this specimen were — 



Expt. I. Positive responses . • ^l 



xr„„„i.,-„„ A Specimen in state of 



JNegative responses . Ov ^ 



Indifferent responses . 22J 



A similar experiment with another individual in an 

 entirely normal nnexcited state, gliding at a moderate rate, 

 gave the following results : 



Expt. II. Positive responses . 20^ 



XT i.- o Specimen in normal 



JSIegative responses . ^\ 



Indifferent responses . ISJ 

 The striking preponderance of the positive reaction in the 

 case of the unexcited individual is notable. The same 

 individual used in Experiment II was now " stirred up " by 

 poking it violently about the dish with a needle for about 

 five minutes. It was then allowed to settle into a glide 

 which was at a more rapid rate than normal, and another 

 series of stimulations was made, with the following results : 



Expt. III. Positive responses . 1^ . 



AT ™ 4-- o Specimen in condi- 



JNegative responses . '^ j . 



T j-£c J o tion of excitation. 



Indifferent responses . 8; 



Here, again, the indifferent responses are in excess, and 

 there are practically no positive reactions. The specimen 

 was again " stirred up " in the same way as before, and 

 another series taken. 



Expt. IV. Indifferent responses (trials 



1 to 11 inclusive) o • • , , ^ 



-r, .^. /, . ■, -ir. opecimen in state of 



Positive responses (trials 12 Y .. .. 



, ^_, excitation. 



and 13) 



Negative responses (0) 



