THE BEHAVIOR OF FUNDULUS 349 



changes from that characteristic of the rising tide to that 

 characteristic of the falling tide before the tide turns. 



At 11.10, i. e. nearly an hour after the pool was closed, the 

 fishes were much more quiet than they had been earlier, Most 

 of them were swimming about in a leisurely fashion, some were 

 feeding and none were coming out of the water. They were 

 observed for some time after' this, but at no time was there the 

 slightest indication of an attempt to leave the water, although 

 various methods were used in trying to make them leave, e. g., 

 boards were thrown into the pool, the water was violently dis- 

 turbed by running around in it and much of it was drawn off. 

 Later the water in this pool together with the fishes was drained 

 into a lower pool. In this pool the fishes swam about rapidly 

 as though they were considerably excited but none of them 

 left the pool, although a few at different times came out of the 

 water a short distance. Their behavior in general was markedly 

 different from that observed in animals suddenly shut in pools 

 during the ebbing tide . This indicates strongly that the all- 

 important factor involved in the behavior resulting in the over- 

 land escape of Fundulus from tide-pools is the sudden closing 

 of the outlet through which it is accustomed to go. The loca- 

 tion of this outlet they evidently remember for some time. 

 The results of this experiment show also that Fundulus becomes 

 very rapidly acclimated. 



The movement of these fishes on land seems to be well co- 

 ordinated. They travel in fairly direct courses. There is 

 nothing in the nature of aimless tumbling about as is ordinarily 

 seen in the behavior of fishes out of water. Locomotion con- 

 sists of successive leaps due to sudden bending of the body. 

 When the fish falls after a leap it may be directed toward any 

 point of the compass, but the succeeding leap carries it on its 

 course no matter in which direction it may be facing at the time 

 of the response. Thus before each leap it may be headed in 

 the direction in which it is traveling or in the opposite direction 

 or in any other direction. It is really remarkable that the 

 bending of the body is so regulated that the animal continues 

 to move in a given direction regardless of its axial position at 

 the beginning of the successive reactions. As to the mechanics 

 of the process I am as yet quite in the dark. And I am also 

 unable to say what factors in the environment serve to direct 



