THE AMPHIBIANS 177 
In geological times many of the salamanders were of 
great size, several feet in length, and some were enclosed 
in an armor consisting of bony plates. All now living have 
the skin naked, and with the exception of the giant species 
of Japan, three feet in length, and a few similar forms in 
America, the modern representatives are comparatively 
Goat PF “ Pes ty hy 7 a i *Th 
Fig. 108.—Blunt-nosed salamander (Amblystoma opacum). Photograph by W. H. 
FIsHER. 
feeble and measure their length by inches. Only a few, on 
account of their bright colors, are particularly attractive, 
while the others are usually shunned and considered re- 
pulsive, chiefly because of their supposed poisonous char- 
acter, though in reality few animals are more harmless. 
169. Tailless forms.—In the frogs and toads the meta- 
morphosis which the young undergo is almost as profound 
as that which takes place with the insects. The gills, to- 
gether with their blood-vessels, disappear completely. The 
tail, with its muscles, nerve-supply, and skeleton, is ab- 
sorbed. The cartilaginous notochord gives way to a jointed 
back-bone. A skull is developed; numerous bones form in 
the limbs, affording an attachment for the powerful muscles 
which make the toad, and especially the frog, expert swim- 
