[April 28th 1916]
shades and graduating tints of colour have, each its special value, and that the frogs gain protection, in different degrees and proportions, by the harmony of these varied pigments with the dull mud or the complex blend of greens and browns and yellows of the streaming water weeds. But in addition to being of survival value to the frogs as a mode of escape from their enemies I suspect that this harmonization of colour with the surrounding vegetation was of importance in capturing food. For insects, their customary food, at this time of year were not abundant, and the frogs, in their absence, largely fed on fish. Their colorations greatly assisted them in this. For the frogs were in the habit of lying motionless amongst the green and yellow water-