TRANSFORMATION OF THE AXOLOTL 143 



represented, 14 of which are found only in the New World. 

 The total number of species in the' Old World is only 36. In 

 North America, the northern boundary of the Order Urodela 

 is a line extending due east and west across the continent 

 about on the 5'-2d parallel of latitude. ("Amphibia and Rep- 

 tiles," Dr. Hans Gadow, pp. 95-96.) 



THE FAMILY OF SALAMANDERS 



Salamandridae 



The members of this Family seem to be engaged in a con- 

 tinuous struggle at the dividing line between lungs and gills, 

 and exhibit all possible variations between perfection in both 

 those organs. One species (the axolotl) changes from water 

 to land with neatness and despatch. Another (the striped- 

 backed salamander) lingers for two or three years in its larval 

 state, in the water, while the blue-spotted salamander lives 

 upon land, in moist forests. But one or two illustrations must 

 suffice for all. 



The Axolotl,^ of Mexico, is in some respects the most 

 striking — even theatrical — example of salamandrine life and 

 character. Its transformation is so rapid and complete that 

 it is highly impressive. As an Axolotl, it is either a dark 

 gray or a perfectly white and almost translucent animal, 

 about 7 inches long, with external gills divided into three 

 long, ragged branches; a long tail with a continuous fin above 

 and below, and four very practical legs. This is the larva. 



If the pond in which this creature lives threatens to dry 

 up, the gills and the fins on the tail and back begin to shrink 



^ Am-hlys'to-ma ma-vor'ii-um. 



