Observations on the Behavior of the Larvae of the Common American Newt During Metamorphosis

To the student of evolution the Amphibia are an extremely interesting group because they are the first vertebrates to have successfully left water and assumed a laind habitat. Among the Amphibia Triturus viridescens viridescens is most interesting in that it shows complete adaptation to a watcr habitat during its larval and adult stages and to a land habitat during its immature '.red eft stage. This peculiar life cycle, together with the facts that it is our mnost widely distributed salamander and that it undergoes adaptation in localities differing greatly as to temperature extremes, humidity, and elevation, make it an ideal form on which to study the adaptive mechanisms involved in the evolutionary changes from water to lan1d and from land to water.