90 GENETICS 



to maturity near the snow-line or in the warm valleys 

 at a lower altitude. 



Marie von Chauvin was able, by decreasing the 

 amount of water in an aquarium, to transform the 

 gill-breathing salamander Axolotl into the land form, 

 Amblystoma, which in its adult form has no gills, but 

 breathes by means of lungs. Both of these forms 

 are sexually mature, reproducing their like, and had 

 long been recognized by systematists as distinct 

 species. 



More recently Kammerer, by similarly reducing 

 the water supply, succeeded in transforming Sala- 

 mandra maculosa, a salamander that normally pro- 

 duces about seventy eggs which, when hatched in 

 water, become gill-breathing tadpoles, into a sala- 

 mander producing only two to seven young which 

 are born alive without gills and are able to live out 

 of water entirely, in damp situations. These land- 

 adapted offspring, moreover, when supplied with 

 abundant water, produce in turn tadpoles which spend 

 days only, instead of months, in the water under- 

 going their metamorphosis, thus showing an appar- 

 ent inheritance of an acquired character. 



It should be pointed out, however, that in these 

 cases the gill-breathing forms in each instance rep- 

 resent a case of arrested development. Axolotl is 

 simply a larval form of Amblystoma that, under nor- 

 mal conditions of an abundant water environment 

 and high temperature, gets no further in its meta- 

 morphosis than the tadpole stage, when it produces 

 eggs and sperms and finishes its life story. A change 



