AMPHIBIANS. 209 
After what has gone before, the transformation of the 
Amphibians needs no elucidation. Their predecessors 
were water-breathers, whose form and mode of life are 
more faithfully preserved by the long-tailed Amphibians, 
the tritons, and salamanders, than by the frogs. In 
our tritons, sexual maturity not rarely commences in 
the larval state, hence in a phase which was definitive 
in the progenitors of the present genera. There is, 
indeed, one species, the Mexican Axolotl, which nor- 
mally propagates itself during the larval phase. Auguste 
FIG, 18. Amblystoma. 
Dumeril’s observation is highly interesting, that of the 
thousands of Axolotls that he bred at Paris, some few 
advanced beyond the grade of development hitherto 
known in them, ze. they lost their gills, changed the 
