A Warning-Color Reaction Experimentally Established. 285 



snapper, such as quinine and red pepper. So far as the experiments went 

 the snappers gave no evidence that these substances were distasteful. A 

 few attempts to feed to the snappers the tissues of the medusa Cassiopea 

 xaniaeUana showed them to be distinctly unpalatable. However disguised 

 in form or color they were rejected after a few trials, presumably on account 

 of the contained nettlc-cclls. The red atherinas were then made unpalatable 

 bv sewing into the mouth of each the branching tip of a tentacle of this 

 medusa. The tentacle had the appearance of food projecting slightly from 

 the mouth. The atherinas thus prepared were thrown from the dock, one 

 at a time, to the assembled colony of about 1 50 snappers. An additional 

 atherina was thrown as soon as its predecessor had been taken or as soon as 

 the behavior of the snappers showed that it would not be immediately taken. 

 The snappers thus had at least one atherina always before them. A record 

 was kept of the behavior of the snappers toward each atherina offered. 



Experiment ^2. — Occupied 3 days. July 16, 18. and 19. lyo/, but is best 

 regarded as a single experiment. The atherinas used had been preserved 

 in 2 per cent formalin. They were rinsed and then allowed to soak for 

 about 2 hours in a large quantity of sea-water. A few of these when 

 offered to the snappers were taken as though fresh. Tentacles of Cassiopea 

 were sewn into the mouths of others in such a way as to leave the fringed 

 end of the tentacle projecting. The tentacled fish were then stained in fast 

 scarlet in the manner described for experiment i, until they were of a bril- 

 liant red color. The effect of this treatment upon the nettle-cells was not 

 positively determined, but the result of the experiment indicates that they 

 remained active. 



Atherinas prepared in this way are referred to as formalin tentacled 

 reds; fish similarly prepared but without tentacles are referred to as for- 

 malin reds; those prepared in formalin and washed but not stained are re- 

 ferred to as formalin normals; while formalin fish provided with tentacle 

 but unstained are referred to as formalin tentacled normals. The behavior 

 of the snappers toward each atherina offered them was recorded under one 

 of the four heads (table n) ; taken at once indicates that the atherina was 

 seized as soon as it struck the water ; taken with hesitation, that i to 3 sec- 

 onds passed before the atherina was seized ; taken with much hesitation, that 

 more than about 3 seconds passed before the atherina was seized; refused 

 indicates that the atherina remained untaken during the time of the series to 

 which it belonged, or else that after the snappers had had abundant oppor- 

 tunity to take it, the tide carried it away, so that it could no longer be 

 observed. Several minutes were required for an atherina to be thus carried 

 away, and this happened only during the first two series of the experi- 

 ment, in which some of the atherinas floated while others sank. In the 

 third series the atherinas were made to sink by slitting the air bladder so that 

 all that remained untaken were accessible to the snappers during the series 

 and for some time afterward. 



