144 TAILED AMPHIBIANS 



and disappear, and the animal begins to breathe air at the 

 surface of the water. Finally, when the transformation is 

 complete, a lizard-like animal with very serviceable lungs, 

 no gills whatever, and not a vestige of fins on tail or back, 

 emerges upon the land, and thereafter leads a terrestrial life. 

 It is then known as a Spotted Salamander; and it is no 

 wonder that for many years these two forms were considered 

 creatures of different species. It was in the Jardin des 

 Plantes, in Paris, that the process of birth, growth and trans- 

 formation was finally discovered. 



It is not difficult to bring about the transformation of the 

 Axolotl, by gradually diminishing the water supply, and thus 

 observing from day to day the progress of the change. More 

 than this, the transformation can be arrested by gradually 

 diminishing the allowance of air, thus forcing the imperfect 

 Spotted Salamander back into aquatic life. At first there is 

 a struggle against life under water, but finally the animal 

 becomes adjusted to it. (R. L. Ditmars.) 



By keeping the larval Axolotl in an aquarium, with an 

 abundance of water but with no encouragement nor facilities 

 for breathing air, it not only remains in that stage indefinitely, 

 but it breeds successfully. 



This species is most abundant in the shallow lakes around 

 the City of Mexico, but it inhabits nearly the whole of Mexico 

 and also a considerable area in the southwestern United 

 States. Unquestionably, the wonderful mobility — as it may 

 truly be called — of this creature is for the purpose of enabling 

 it to survive in a region wherein droughts are common, and 

 where the life of an aquatic animal depends upon its ability 



