268 Papers from the Marine Biological Laboratory at Tortugas. 



shown in table 2. To call together the snappers 3 atherinas were thrown 

 at the beginning of each experiment. These were either normal or stained 

 red, but were not rendered disagreeable. The first 2 of these (experiment 

 11} were taken with some hesitation, but all other atherinas offered in the 

 nine experiments were taken as readily as normal fish. If any of them had 

 been subsequently rejected their red color wotild have made them conspicu- 

 ous objects on the sand bottom. None were seen to be rejected. In two 

 cases the fish, after being taken, were swallowed slowly. They could be seen 

 protruding from the mouth of the captor, which, pursued by other snappers, 

 slowly swallowed them. The substances used are as disagreeable to man as 

 any that I know, some by reason of their taste, others on account of their 

 odor or because they act as irritants. Probably none of them occur normally 

 in the environment of the snapper. 



.\B NORMAL FORM. 



To test the behavior of the snappers toward food of abnormal form, 

 normal atherinas were modified in form as shown in e.xperiments 20 to 23. 



Experiment so: By removing the body between the anal and pectoral 

 fins and sewing together the head and tail so as to produce a very much 

 shortened form. 



Experiment 21: By removing the heads of two individuals and sewing 

 the bodies together end to end so as to produce a very much elongated 

 fish with a tail at each end. 



Experiment 22: By sewing together the bodies of three fish after removal 

 of the heads and tails and thus forming a flat rectangular piece. 



Each of the modified forms was thrown to the snappers separately after 

 a number of normal atherinas had been thrown to assemble them. The 

 first (experiment 20) was taken with a little hesitation, but the rest were 

 taken as readily as the normal fish. Separate heads and separate tails of 

 atherinas were taken with the same readiness. 



Experiment 2^: A piece of white twine 12 inches long and about 0.04 of 

 an inch in diameter was tied by one end about the head of an atherina. 

 It was thrown after one normal fish and taken at once. 



Experiment 24: A brown cord about 13 inches long and a sixth of an 

 inch in diameter was tied by one end about the head of an atherina. This 

 was thrown after a single normal atherina. There was a moment's hesita- 

 tion, three snaps which fell short, and then the fish and cord were taken. 



Experiment 2j: An atherina was wrapped in cheesecloth and this rubbed 

 with another atherina. It was thrown after a single normal atherina and 

 was at once taken and was not seen to be rejected. 



From the preceding experiments it appears that modifications in the 

 color, form, and chemical properties of the normal food do not prevent the 

 gray snapper from taking it. The number of snappers involved in the ex- 

 periments is so great that it is improbable that any individual had more 



