SPAWNING BEHAVIOR IN FUNDULUS HETEROCLITUS. 323 



plumage" and became decidedly pale. The females too seemed 

 to have forgotten about spawning in their anxiety to become 

 familiar with the new neighborhood. On the following day the 

 fish were still uninterested in spawning and I concluded that they 

 had passed the sexual climax while they had been busy with 

 their explorations. 



Experiment j. - - I put several males that had been isolated 

 for several days into an aquarium containing only females. 

 These had been extruding eggs at intervals, but as soon as the 

 males appeared, they seemed to become excited and immediately 

 began to take up spawning attitudes and to extrude eggs in 

 much increased amounts. It seems certain that the presence of 

 the male, even when the latter refrains, as in this case, from any 

 participation in the spawning act, exercises an exciting influence 

 upon the female. The stimulus is probably a visual one, for the 

 appearance of the male is very characteristic. 



Additional observations : 



1. Occasionally pairs were observed to come together and 

 spawn in open water without being in contact with any solid. 

 It was also not unusual to see them spawning against the bottom 

 instead of against some more or less perpendicular object. 



2. On three occasions I observed a female following a male 

 around and apparently endeavoring to incite him to spawn with 

 her by bumping him and placing her body in contact with his. 

 On one occasion she succeeded in inciting him to clasp her for 

 an instant. This assumption of the initiative on the part of the 

 female struck me as being decidedly abnormal and may have 

 been a perversion of instinct, due to confinement. 



3. I observed that females that were being guided about by 

 the males occasionally seemed to resent this infringement upon 

 their liberty and engaged in a somewhat mild form of contest 

 with the males, returning their butting in kind. The male, how- 

 ever, invariably seemed to have his way in the end. 



4. On June 27, I observed F. Jicteroclitns spawning in the Eel 

 Pond in the shadow of a boat and in about eighteen inches of 

 water. The males would chase females out beyond the shadow 

 but usually returned quickly to the shade. I have noticed 

 repeatedly that the fish prefer the darker places for spawning. 



