Adaptation to External Conditions

Abstract

THE curious modification of adaptation to external conditions in the case of the Salamandra atra, which I have more than once brought under the notice of naturalists, but which I myself first noticed under the direction of Prof. von Siebold, has been cited by Mr. Darwin (“Origin of Species,” 4th Ed. p. 534) in confirmation of his views. I revert to it now for the sake of its illustration of a new and striking observation, which has excited the incredulity of several eminent naturalists in France—an incredulity, we may suppose, founded on their ignorance of the previous observation. The fact to which I called attention was this: The ordinary salamander, or Newt, is born in the water as a tadpole, and in the water it completes its metamorphosis. But the Salamandra atra, living high up in the mountains, with no pools in which to pass its tadpole existence, is born on the land, a completely formed animal; that is to say it passes through the tadpole stage while still within its mother's body. I have taken it from the gravid female in this tadpole state, and placed it in water, wherein it swam as if that were its natal element.