Figure 10 



One of the most interesting of the many species of tailed Amphibians is 

 the Axolotl (Ambly stoma mexicanum). This species usually retains the large 

 functional gills, as shown here, throughout life. Under other conditions, 

 apparently endocrine in nature, metamorphosis occurs and the gills are lost. 

 The animals shown are a white variety — a rare condition which has arisen 

 in captivity. They have been bred in the Osborn Zoological Laboratory 

 for several generations, and many of the embryos used in experimental em- 

 bryology. 



151 



