ICHTHYOPSIDA. 249 
which are found in Java, Ceylon, South America, and Guinea. The 
body is entirely destitute of limbs, and is enclosed in an integu- 
ment which is thrown into numerous transverse wrinkles, and 
sometimes has numerous horny scales embedded init. The eyes 
are concealed by the skin, and are rudimentary. There is no 
tail, and the anal aperture is placed almost at the extreme end 
of the body. When adult, respiration is carried on by means of 
lungs, but gills are present in the young, and there can therefore , 
be no doubt as to their being genuine Amphibians. 
The Cecilie are found burrowing in marshy ground, and 
they are not unlike large earth-worms in appearance, but they 
sometimes attain a length of several feet. 
ORDER II. URODELA or ICHTHYOMORPHA (Gr, zchthus, a 
fish ; and sorphe, shape).—In this order are a number of fish- 
like Amphibians, of which the Newts and Land-salamanders 
are the most familiar examples. In all the members of this 
section the skin is naked, and never develops any hard struc- 
tures, and in all there is a well-developed fish-like tail, which is 
retained throughout life. The vertebrae are sometimes hollow 
at both ends (amphicelous), sometimes hollow behind and con- 
vex or rounded in front (opzsthocelous). The ribs are rudimen- 
tary, and the bones of the fore-arm (radius and u/na), and of 
the shank (¢zéza and fibula), are separate, and are not combined 
so as to form single bones. 
The Jchthyomorpha are not unfrequently spoken of as the 
“ Tailed” Amphibians (Uvodela), and they fall into two natural 
sections, according as the gills are permanently retained through- 
out life, or are cast off before maturity is attained. The animals 
belonging to the first section are often called “ perennibran- 
chiate,” whilst those belonging to the second are said to be 
‘* caducibranchiate.” 
Among the Perennibranchiate forms, in which the gills are 
permanently retained after the lungs make their appearance, 
the best-known examples are the Axolotl (fig. 134), the curious 
Proteus anguinus, and the Mud-eel (Szvex). The Axolotls 
inhabit various of the lakes of the American continent, the best- 
known species being the Szvedon pisciforme of the Mexican 
lakes (fig. 134). It attains a length of a foot or more, and 
possesses both pairs of limbs, the fore-feet having four toes, the 
hind-feet five toes. The branchiz are in the form of three long 
