294 Papers from the Marine Biological Laboratory at Tortugas. 



cniikl be observed in the way in which red and white fish were taken by 

 individual snappers or by the colony as a whole. Absence of hesitation in 

 taking tentacled fish is attributable in the beginning to inexperience. That 

 30 tentacled fish should be so taken is no doubt due to hunger, since this 

 colony had received less food than any other. The hesitation and refusal 

 shown toward red by the laboratory colony is therefore attributable to expe- 

 rience gained during experiment 32. It is neither instinctive nor the result 

 of a previously formed habit. 



In 1905 an experiment was carried out differing from that described 

 in the present section only in that the atherinas used were fresh, not pre- 

 served in formalin. Excluding some very brief preliminary trials the ex- 

 periment of 1905 extended over but a single day. Between 9" 48™ and 3" 11"' 

 p. m. there were fed to the laboratory colony of about 100 snappers 117 

 fresh tentacled red atherinas, divided into lots of from 8 to 20, offered at 

 intervals of 30 to 60 minutes; 20 of these, including the last 8, remained 

 untaken, although normal fish were taken readily at all times. The experi- 

 ment of 1907 is an extension and confirmation of that of 1905. 



The results of these experiments may now be briefly stated as follows : 



When red atherinas, rendered unpalatable by attaching to each a 

 part of a tentacle of Cassiopea, are oft'ered to a colony of gray snap- 

 pers, they are at first taken instantly, later taken after the lapse of a 

 longer or shorter time, and finally refused. In 1907 (experiment 32) 

 the final refusal resulted (omitting series II) from feeding to about 

 150 snappers, 238 formalin tentacled red atherinas, of which 178 were 

 taken and 60 refused. The feeding required i hour and 25 minutes, 

 divided into 2 periods of 35 and 50 minutes, separated by an in- 

 terval of 3 days. In this time there was an average of but little more 

 than one unpalatable atherina taken for each snapper. This sufficed 

 to form for the snappers an association between red and the quality 

 or qualities which rendered the atherinas unpalatable of such a sort 

 that formalin red atherinas were thereafter refused. Formalin red 

 atherinas were refused even when not tentacled, while formalin 

 normal atherinas (uncolored) were taken whether tentacled or not, 

 hence the association is between color and the quality which renders 

 the atherinas unpalatable, not between the form of the tentacled ather- 

 inas and that quality. In a second colony of snappers formalin red 

 atherinas were taken readily, in considerable numbers (experiment 

 33) whether tentacled or not, hence their refusal by the first colony 

 can not be attributed to an instinctive or habitual avoidance of red. 

 Their acceptance by the first colon}' at the beginning of experiment 

 32 points to the same conclusion. 



The statement seems therefore warranted that in experiment 32 

 the color came to have for the snappers a warning meaning. A 

 warning color was artificially established. This result w-as reached 

 in spite of the fact that atherina is the normal food of the gray snap- 

 per at the time of year at which the experiments were made. By 

 changing the color of this food and rendering it unpalatable the 



