354 ON CHANGE OF MEXICAN AXOLOTL TO AN AMBLYSTOMA. 



Cope* asserts tlie same thing quite decidedly ; nnd individuals bred 

 by him in America from the Siredon Blexicanus, also in captivity, "showed 

 CO inclination to the transformation." On the other hand, Tegetmeiert 

 saw the change begun in one of five individuals which traced their 

 descent to the Lake of Mexico and so the second fact is established, 

 that also ilie genuine and real Axolotl under certain circumstances changes 

 in confinement to an Amhlystoma. 



This remark would be superfluous, if it were, as was long believed, 

 true that the Axolotl of the Paris Garden of Plants, whose metamor- 

 phosis was first observed and excited so much attention at the time, 

 actually belonged to the species Siredon Mexicanus, the only Siredon 

 which in its home bears the name Axolotl. 



In his first communication, Dnmdril himself was of this opinion ; he 

 called the creature ^^ Siredon Mexicanus^^ syn. Humboldii;X bat later, in 

 his detailed work§ on the change of the Axolotl contained in the Gar- 

 den of Plants, he recalled this view, and, after a critical examination of 

 the five described Siredons, came to the conclusion that the Axolotls in 

 the possession of the Paris Museum were probably Siredon lichenoides 

 Baird. 



So all the transformations of Axolotls observed in Europe were to be 

 referred to this species ; for — at least so far as is known — they are all 

 descendants of the Paris colony. Thence also, indirectly, came the sub- 

 jects of my experiments. 



To be sure, now it does not agree with this, that the Amblystoma 

 form, which Dum6ril obtained from his Axolotls, corresponded with 

 Amblystoma tigrinum Cope, while we learn by Marsh || that Siredon 

 lichenoides Baird changes to Amblystoma mavortium Baird when it under- 

 goes the complete metamorphosis. Marsh found the Siredon lichenoides 

 in Alpine lakes (7,000 feet above the sea), in the southwestern portion of 

 the United States (Wyoming Territory), and by breeding in aquariums 

 obtained from \tihQ.Amblystomamavortium^A\v(\. Nevertheless, he holds 

 it doubtful whether the animal ever goes through the change in its 

 home; to be sure, without any sure foundation and on purely theoretical 

 grounds, namely, because in his judgment "the colder temperature 

 there is less favorable to it " ^ 



If I doubt the correctness of this last opinion, it is only because the 

 Amblystoma mavortium in a state of nature has been found in many 

 parts of the United States, namely, in California, New Mexico, Texas, 



* Dana and Silliman, Amer. Jnurn., 3cl series, i, p. 89. Annals Nat. Hist., vii, p. 24G. 



t Proceed. Zool. Soc. 1870, p. 160. 



t Compt. Eend., tome GO, p. 765 (186.5). 



$ Nouvelles Archives du Mns6um d'Hist. Nat. Paris, 1866. Tome ii, p. 268. 



II Proceed. Boston Soc, vol. xii, p. 97 ; Silliman, Amor. Journ., vol. xlvi, -p. 364 ; a 

 reference to this in Troscbel's Jahresbericht for 1868, p. 37. 



H Proceed. Boston Soc, vol. xii, p. 97; Silliman, Amer. Journ., xlvi, 364. I could not 

 examine these works myself, and qnote from the reference in Troscbel's Jahresbericht, 

 1868, p. 37. 



