THE BEHAVIOR OF FUNDULUS ' 345 



escape. This is repeated, one group following another, until 

 all or nearly all have escaped. 



In this way I have seen more than 200 of these fishes leave 

 a tide-pool 50 meters long, 13 meters wide and 30 cm. deep, 

 and travel across a sand-bar more than 3 meters wide and 10 

 cm. high, all in the course of half an hour. And I have seen 

 them proceed in a fairly direct course toward the sea even against 

 a moderately strong wind. I have also seen them persistently 

 attempt, continuously for at least a minute, to go overland 

 to the sea against a wind so strong that they could make no 

 headway. When I first saw this performance I was deeply 

 impressed. I had often seen fishes, when thrown on the land, 

 flop back into the water in a more or less aimless fashion, but 

 I had never seen any voluntarily leave a body of water and 

 travel in a coordinate way on land. Concerning the nature 

 of this phenomenon and the regulation in direction of locomotion 

 on land I shall have something to say presently. 



The description given above is based upon numerous exper- 

 imental observations among which the following are typical. 



1. On August 30 a tide-pool containing numerous specimens 

 of Fundulus majalis was discovered on a sandy beach. This 

 pool, somewhat irregular in outline, had a maximum length 

 and width of 50 and 13 meters respectively and the water in 

 much of it was, in places, more than 20 cm. deep. A strong 

 current about 3 cm. deep was running out through the outlet, 

 and some of the specimens were continuously passing out or 

 in through it. At 5 P. M. all in the immediate neighborhood 

 were driven in and then the outlet was suddenly closed with a 

 board which extended 5 cm. above the surface of the water. 

 A ridge of sand 60 cm. long and 10 cm. high was thrown up at 

 either end of the board. This ridge extending 16 cm. above 

 the water in the pool, joined on one side of the outlet, a natural 

 bar of sand of the same elevation, so that the pool was separated 

 from the sea on this side by a continuous barrier having an 

 elevation of 15 cm. On the other side however, the natural 

 bar had an elevation of only 5 cm. On this side in the angle 

 between the ridge and the outlet, there was a considerable 

 depression containing a small pool of water connected with the 

 outlet, as represented in figure 2. The sand-bar was at every 

 point over three meters wide. The bank at the edge of the pool 



