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THE AMERICAN NATURALIST [Vol. LIV 



the fish will convey themselves overland by flopping in the gen- 

 eral direction of the ocean. Mast shows that the fish are able to 

 keep their sense of direction in the overland course and concludes 

 that they remember the outlet. He believes that since there are 

 apparently no external factors capable of guiding them, the 

 behavior is dependent on internal factors. 



Fundulus heteroclitus does not as a rule leap from pools, when 

 left by the gradually receding tides. Two permanent pools were 

 available for the study of the reactions of this species, one of 

 them being connected with the Raritan River by a drainage ditch 

 during the course of the study. This pool had been under con- 

 tinuous observation in an undrained condition and through an 

 error workmen ran a drainage ditch to it, which did not, how- 

 ever, completely remove the water. After two days of the re- 

 sultant condition the ditch was plugged with heavy sods and 

 observations continued as before. The day after the ditch was 

 plugged it was noted that there were many F. heteroclitus scat- 

 tered all around the margin of the large oval pool. Although it 

 was 25 X 15 ft., there was no marked variation in the distribu- 

 tion of the dead fish, except that there were none at the end 

 farthest from the outlet. The banks were gently sloping and 

 afforded an easy egress in any direction. The second pool with 

 an outlet was long and narrow with high banks and was partially 

 drained at the ebbing of the tide. "When the receding water had 

 left certain of the fish near the shallows at the exit, there was 

 the usual attempt of the majority of fish to follow an outflowing 

 current. But few individuals were caught in the mud, the ma- 

 jority returning to the deeper pool. 



Since there is one predominant reaction in fishes, that to cur- 

 rents, it is quite probable that with Fundulus heteroclitus there 

 is a less marked reaction to ebb tide. In the case of Fundvlus 

 niajnlis under natural conditions there must be an extremely 

 rapid reaction to the condition of slack tide. Their disturbance 

 under experimental conditions induced by Mast (1915), who 

 plugged the entrance of the tide as it was coming in. indicates 

 that this species does not normally accommodate itself to still 

 water and that its stay inland is determined only by the tidal 



In the ease of Fundulus heteroclitus, which migrates inland 

 to the extremely shallow water covering the salt marshes at high 

 tide, there is no such immediate response to receding water. The 



