The Transformation of the Mexican Axolotl. 569 



Axolotl in its native habitat does not undergo 

 metamorphosis or does so as exceptionally as in 

 Europe. Unfortunately in his papers Dumeril 

 gives no precise statement respecting the locality 

 of this species imported from " Mexico " it is 

 probable that he was himself unacquainted with 

 it, so that I can only state on the authority of 

 Cope that Amblystoma has never been brought 

 from south of the provinces of Tamaulipas 

 and Chilhuahua, /'. e. south of the Tropic of 

 Cancer. 9 



This last statement, however, gives no certainty 

 to the matter. Of much more importance is the 

 above-mentioned fact, that the true Axolotl of the 

 lakes about the city of Mexico does not, as a rule, 

 become transformed into an Amblystoma in that 

 locality, although this species in certain cases 

 undergoes metamorphosis when in confinement. 

 From this circumstance and from the fact that the 

 Paris Axolotl likewise experienced but a very small 

 percentage of metamorphosis in captivity, we may 

 venture to conclude that this species also, in its 

 native habitat, either does not become transformed 

 at all or does so only exceptionally. 



But there is yet another body of facts which 

 come prominently into view on considering the 

 history of the transformations. I refer to the 

 existence of numerous species of Amblystoma in a 

 natural state. In the " Revision of the genera of 

 Dana and Silliman's Amer. Journ. See note 3. 



