THE REACTIONS OF THE BLIND FISH, AMBLY- 

 OPSIS SPEL^US, TO LIGHT. 1 



FERNANDUS PAYNE. 



Introduction. 



In the Woods Hole Biological Lectures ('99) Dr. Eigenmann 

 gave the results of some experiments to determine the reaction 

 of Amblyopsis to light. He recorded that : 



1. Amblyopsis seeks the dark regardless of the direction of 

 the rays. 



2. An individual coming from a dark chamber into a lighted 

 one shows signs of uneasiness. 



3. A light ray thrown on fishes from a mirror causes uneasiness 

 in from one to five seconds. 



4. Bright sunlight causes the fishes to swim uneasily. 



5. A lighted match held above an aquarium, which had been 

 in the dark, caused two fishes in one instance to dart to the bot- 

 tom. In another case it produced a very general and active 

 movement among forty individuals. 



6. Different colors do not cause different reactions. 



7. In an open pool, the fishes remained under rocks during the 

 bright part of the day. 



It is the purpose of the present paper to repeat some of his 

 experiments, but in a different way ; to add others, to give data 

 in full of how the fishes react and to determine why they react. 

 The special interest in the problem lies in the fact that we are 

 dealing with a blind animal, whose remote ancestors possessed 

 well-developed eyes. 



Part of the work was done at the Indiana University cave farm 

 at Mitchell, Indiana ; the remainder at the university. All the ma- 

 terial used was caught in the caves at Mitchell. 



These fishes are very sensitive to mechanical stimuli and with 

 this in mind every possible precaution has been used to eliminate 

 them. At Mitchell the cave was used as a laboratory and the 



1 Contributions from the Zoological Laboratory of Indiana University, No. 89. 



3 l 7 



