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 



