CHAPTER XLII 
THE ORDER OF TAILED AMPHIBIANS 
URODELA 
The members of this Order are readily dis- 
tinguished from the preceding group by the pos- 
session of tails, which they retain throughout 
their lives; by their gills, which most of them 
retain permanently; by the absence of scales, 
and by the fact that with very few exceptions 
they are strictly aquatic. It is safe to say that 
any four-legged aquatic creature having a tail 
but no scales, is either a salamander, newt, mud- 
puppy or siren. 
The Order U-ro-de'-la is the dividing line 
between the finny, gill-breathing fishes, and the 
four-legged, lung-breathing, land-going lizards. 
Strange to say, its members are most abundant 
in the temperate regions of the earth, and except 
in two or three small areas, are absent from the 
tropics. In Australasia there are none, and in 
South America and Africa there are none save in 
their extreme northern portions. 
Of all countries, the region embracing the 
United States and the southern provinces of 
Canada is by far the richest in species belonging 
to this Order, the total number present being 
fifty-two. Mexico and Central America con- 
tribute fourteen more, all salamanders. In 
this total of sixty-six species, eighteen genera 
are represented, fourteen of which are found 
only in the New World. The total number of 
species in the Old World is only thirty-six. In 
North America, the northern boundary of the 
Order Urodela is a line extending due east and 
west across the continent about on the 52d 
parallel of latitude. (“Amphibia and Reptiles,” 
Dr. Hans Gadow, pp. 95-6.) 
THE FAMILY OF SALAMANDERS. 
Salamandridae. 
The members of this Family seem to be en- 
gaged in a continuous struggle at the dividing 
line between lungs and gills, and exhibit all pos- 
sible 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) lin- 
gers 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 , 1 of Mexico, is in some respects 
the most striking — even theatrical — example 
of salamandrine life and character. Its trans- 
formation 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 trans- 
lucent 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 threat- 
ens to dry up, the gills and the fins on the tail and 
back begin to shrink, and disappear, and the ani- 
mal begins to breathe air at the surface of the 
water. Finally, when the transformation is 
complete, a lizard-like animal with very ser- 
viceable lungs, no gills whatever, and not a ves- 
tige of fins on tail or back, emerges upon the land, 
and thereafter leads a terrestrial life. It is then 
known as a Spotted Salamander; and it is no 
wonder that for many years these two forms were 
considered creatures of different species. It was 
in the Jardin des Plantes, in Paris, that the 
process of birth, growth and transformation was 
finally discovered. 
It is not difficult to bring about the transfor- 
mation of the Axolotl, by gradually diminishing 
the water-supply, and thus observing from day to 
day the progress of the change. More than this, 
the transformation can be arrested by gradually 
diminishing the allowance of air, thus forcing the 
1 Am-bly' slo-ma ma-vor'ti-um. 
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