AMPHIBIOUS VERTEBRATES. 197 
blind * Batrachian found in the subterranean caves of 
Adelsberg in Carniola, Austria. 
FIG. 239.—Froteus of Carniola caverns, showing the external gills. 
7a 
Notre.—They are pure white, have bristling gills and gill-openings, 
and small teeth. The limbs are four in number, the fore pair having 
three toes and the hinder pair two. They breathe under water by the 
gills and above by lungs, while experiment has shown that the former 
can be removed without injuring them. The mud-puppy (Wecturus) 
of the United States is a familiar form in the Mississippi country and 
upper New York. The body is broad and flat; each foot has four 
toes; they attain a length of two feet. They are extremely sluggish, 
living in muddy water. The eggs are about the size of peas. 
Order III. Tailed Amphibians (Urode/2).—In this 
order the gills are generally only present in the early 
stages; the body is slender and eel-like. The Congo 
snake (Fig. 240) has extremely delicate limbs, and inhabits 
the muddy waters of the Southern States. The hell- 
bender, or AZenotoma, found in the Mississippi Valley, pos- 
sesses permanent gills, is flat, with weak limbs and a prom- 
* The eyes of the Proteus are destitute of a crystalline lens, although 
they have a retina. 
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