The Transformation of the Mexican AxolotL 607 



but they were never carried on for a sufficient time 

 to entirely allay the suspicion, that the specimens 

 concerned would perhaps have undergone the 

 ordinary metamorphosis if their existence had been 

 prolonged. 



Thus, Schreibers " relates that " by confining 

 tadpoles of the salamander found at large in their 

 last stage of growth, under water by means of an 

 arrangement (net ?), and feeding them with finely 

 chopped earthworms, he was able to keep them for 

 several months and indeed throughout the winter 

 in this condition, and in this way to forcibly defer 

 their final change, and their transition from the tad- 

 pole stage to that of the perfected creature during 

 this period/' It is not stated whether the animals 

 finally underwent transformation, so that it cannot be 

 decided whether we have here a case of reversion 

 or simply one of retarded development. That 

 metamorphosis may occur after a long period of 

 time, is shown by experiments upon the tadpole 

 of Pelobates conducted by Professor Linger in 

 Vienna." The creatures were kept in deep water 

 in such a manner that they were not able to land, 

 and by this means three out of a large number 



* " Uber die specifischc Verschiedenheit des gefleckten uml 

 des schwarzen Erdsalamanders odcr Molchs, und der hochst 

 mcrkwiirdigen, ganz eigenthiimlichen Forlpflanzungswei.se des 

 I.< t/tercn." Isis, Jahrg. 1833, p. 527. 



* The experiments referred to have not been made known ; I 

 am indebted for them to a written communication kindly 

 furnished by an esteemed colleague. 



