Fig. 7. Group Activity of Sooty Terns.

animals possessed poisonous or disagreeable qualities which rendered them unpalatable, so that their enemies soon learned to recognize them as uneatable, and thus the more conspicuous their appearance, the more surely were they protected.

It has been assumed that the beautifully colored fish which swim so unconcernedly and slowly in and out among the caverns of the coral reefs were good examples of warning coloration, for over the sandy

Fig. 8. Groups of Nesting Sooty Terns.