562 Studies in the Theory of Descent. 



others, did not emerge from the water at the first 

 ecdysis, but at the time of the fourth. 



"All the Axolotls are now (July, 1875) living, 

 and are healthy and vigorous, so that with respect 

 to their state of nourishment there is nothing to 

 prevent their propagating. Of the first four the 

 largest is fifteen centim. long ; Axolotl No. V. 

 measures twelve centim. 



" The preceding statements appear to demon- 

 strate the correctness of the views advanced in the 

 Introduction : Axolotl larvae generally but not 

 always complete their metamorphosis if, in the 

 first place, they emerge sound from the egg and 

 are properly fed ; and if, in the next place, they are 

 submitted to the necessary treatment for changing 

 aquatic into aerial respiration. It is obvious that 

 this treatment must only be applied very gradually, 

 and in such a manner as not to overtax the vital 

 energy of the Amphibian." 



To the foregoing remarks of Fraulein v. Chauvin 

 I may add that in all five cases the transformation 

 was complete, and not to be confounded with that 

 change which occurs more or less in all Axolotls 

 in the course of time when confined in small glass 

 vessels. In this last case there frequently appear 

 changes in the direction of the Amblystoma form 

 without the latter being actually reached. Jn the 

 five adult Axolotls which I possessed for a short 

 time, and of which two were at least four years old, 



