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pigeons with bills so short that they could not feed themselves, and the old ones actually had to be fed by hand, otherwise they would have soon starved. Again we have in this country certain aquatic batrachians called amblystomas; they are related to the tritons, salamanders and newts, and some people call them water-lizards, as they possess the general shape of a lizard and, in the case of the amblystomas, at least, they spend a certain part of their existence in the water. Now in New Mexico they have Arnhlystoma tigriniim, and when they are found in shallow water, or pools with light-colored clayey bottoms, the amblystomas themselves are of pale tints and this also may, to some extent, be due to their food. A number of years ago, when I was living in New Mexico, I captured a great many of these amblystomas, several hundred for the Smithsonian Institution, and others for a German lady who was experimenting with them in Berlin. I also experimented with them, as the amblystomas possess what may be termed very plastic organizations. I found that by keeping them in perfectly clear water in deep glass jars, and feeding them heartily for months on raw beef and nothing else, they changed very markedly in appearance, and besides they became of a deep black color, and in the course of time came to look totally unlike their kin in nature. This was a case where surroundings and food produced the variation, but the latter was due to laws over which I had no control, and, in fact, could not fully explain, yet I soon came to know that if I took from its natural environment in nature a pale brown amblystoma that was more or less slender and agile and desired to produce a stouter and more sluggish