258 REPTILES AND BATRACHIANS 



Although suspected by Cuvier to be but the larva of 

 some unknown salamander or newt, the Axolotl of Mexico 

 was for many years regarded as solely aquatic. In the year 

 1863 a number of living specimens were imported for the 

 first time to Europe, where some of these, kept in the 

 Jardin des Plantes, in Paris, bred and the young were 

 successfully reared. At the time there seemed no possible 

 doubt that the Axolotl, having bred in the branchiate con- 

 dition, could be anything but a perfectly aquatic animal. 

 It was not, however, until some two years later that the 

 subject assumed a different aspect, for some individuals of 

 the second generation lost their gills and the fins of the 

 back and tail, developed eyelids and yellow spots on 

 the skin, and finally took to land, transforming into the 

 terrestrial salamander, already well known from North 

 America, under the name of Amblystoma ttgrinu?n. 



A few years later. Mile, de Chauvin, at Freiburg Uni- 

 versity, tried to solve the question as to whether it were 

 possible to force the larvae, if brought under conditions 

 which rendered the use of the gills difficult, and that of the 

 lungs easy, to change into Amblystomes, and, therefore, 

 took several broods of Axolotls about six months old and 

 placed them in large glass vessels, which were so disposed 

 and the water so restricted that at one spot only could they 

 dive quite under, while everywhere else they came into 

 contact with the air. The water was then gradually 

 reduced. Within a few days a change took place, the 

 creatures leaving the water in from four to fourteen days, 

 the complete metamorphosis following about ten days 

 later. Mile, de Chauvin summarized her results as 

 follows : " From what I have said, the correctness of the 

 view suggested by Weismann must be established, namely, 



