AXOLOTLS AND AMBLYSTOMES. 389 
go through their metamorphosis in the same regular way as do 
the rest of the members of the Salamandridw. And I think Tam 
correct in saying that, in their native lakes near the city of 
Mexico, the Axolotls never now become transformed into 
Amblystomes. 
Professor Weissmann explains this peculiar and uncertain 
metamorphosis of the Axolotl by remarking that when the 
ancestors of the Axolotls passed through the ordinary changes 
which occur in the usual life-history of 4. tiyrinwm, the climate 
in the neighbourhood of Mexico was sufficiently moist to allow 
members of the Salamandride to live while in a mature condition 
upon the land. But now, since the climate, for reasons, has 
become too dry for these creatures to live as terrestrial animals, 
they remain throughout their lives in the water, where they 
breed while still in a larval state. 
The change, therefore, which takes place under certain condi- 
tions in confinement is really what is called atavism, 7.e., the 
resemblance of offspring to some remote ancestors, instead of to 
immediate parents. 
Axolotls are very easily kept in captivity, where they will live 
for a great many years. They feed readily upon worms, tadpoles, 
small fish, newts, and raw meat. If properly cared for, they are 
almost sure to breed regularly every year, depositing their eggs 
among the weeds, or on stones and pieces of rocks, which should 
be placed in the water in which they live. 
Directly the eggs are noticed, either they or the parent 
Axolotls should be removed from the tank. The eggs will hatch 
in about a month, or even much sooner than this, if they are 
kept in water of a high temperature. When the tiny tadpoles 
are hatched, they should be treated exactly according to those 
directions which have been given for the rearing of young Newts 
and Salamanders. An Axolotl is very like a Newt whiie in its 
branchiate state, and the early development of the two animals is 
almost identical. 
Axolotls of different sizes and ages ought never to be associ- 
ated together, or the larger Batrachians are certain to prey upon 
the smaller ones. When fully grown, several Axolotls may be 
kept together. 
