BIOLOGY, MARINE — MAYER. IIQ 



Prof. Jacob Reighard carried out a series of ingenious and pains- 

 taking experiments upon the possible ability of predaceous fishes to 

 distinguish warning color, if such exists, in the brilliantly colored 

 fishes of the coral reefs. The very remarkable display of beautiful 

 color among the smaller reef-fishes has commonly been supposed to 

 serve as a warning to possible enemies, and to be associated with 

 distastefulness or poisonous qualities. This hypothesis of warning 

 coloration has become one of the fundamental corollaries of the 

 theory of natural selection. Yet it rests upon but little experimental 

 evidence, and practically none in so far as fishes are concerned. 



Professor Reighard's experiments have thrown much light upon 

 this crucial problem, and no more conclusive experiments have ever 

 been made upon the subject of warning coloration. It is to be hoped 

 that his researches in this direction may be largely extended. His 

 preliminary report is presented herewith : 



Preliminary Report of Jacob Reighard upon Warning Coloration in 



Reef-Pishes. 



I studied the habits and adaptations of the coral-reef fishes with a view 

 to a possible explanation of the remarkable diversity of form and color which 

 they exhibit. Most of my time was spent in a preliminary investigation of 

 warning color. 



The gray snapper (Neomaeiiis griscus), the commonest predaceous fish of 

 the region, was experimented on in mass and without removing the fish from 

 its natural environment. The purpose of the experiments was to determine 

 whether warning color is possible in the case of these fish, and whether any 

 of the bright-colored fish of the region actually are warningly colored for 

 the gray snapper. 



The commonest food of the gray snapper is a very abundant, small silvery 

 fish, Atherina laticcps. By imparting to Atherina a variety of brilliant arti- 

 ficial colors it was learned that none of these colors in themselves acted as 

 warning colors for the gray snapper. In the same manner it was shown that 

 the gray snapper is not color-blind, but distinguishes colors, or at least, cer- 

 tain colors. When the colored Atherinas were given a variety of odors or 

 tastes, most unpleasant to man but not normal to the environment of the fishes 

 (40 per cent formaldehyde, pure clove oil, carbon disulphide, formic acid, 

 quinine, red pepper, etc.), they were still eaten by the hungry gray snappers, 

 and without appreciable hesitation. But when there was imparted to the 

 colored Atherinas a disagreeable quality normal to their environment, there 

 was soon established for the gray snapper a transient association between 

 the unusual color or unusual form of the Atherinas and the unpleasant quality 

 of taste or smell. Thus blue Atherinas to which were attached portions of 

 Medusse (Cassiopca) containing nematocysts were at first taken readily, but 

 after two or three hours they were refused. Pieces of the arms of Cassiopea 

 that were shaped and colored so as to closely resemble Atherina, were at first 

 taken, but after a very few minutes were refused. Thus an artificial warn- 

 ing, whether of color or form, was established, and by means of it the modi- 



