200 BACKBONED ANIMALS. 
the others being placed with equal care. Our common 
triton lays its eggs singly on submerged plants ; others 
are connected by a thread, whether on land or in the 
water. 
Order IV. Blind Snakes (Gymnophiona).—The ani- 
mals of this order are snake-like only in external appear- 
ance and in name, having elongated cylindrical bodies 
destitute of legs. The skin is smooth, containing imbed- 
ded scales, and some species secrete in small pores a vis- 
cous secretion similar to that of snails. The eyes are small 
and beneath the skin. The Cec/ia of the tropics attains 
a length of several feet, and lives underground like the 
earth-worm, feeding upon insects. A Surinam species is 
viviparous ; the young are born in the water and have 
external, leaf-shaped gills, that are absorbed as they 
leave it. 
Order V. Tailless Amphibians (Azura).—We now 
come to the frogs and toads, in which the body is short, 
thick, and tailless in the adults, with four limbs, the hind- 
er pair adapted for leaping. The skin covers the body 
loosely, the muscles not adhering to it. The tongue is 
fastened to the front of the jaw, the tip pointing down 
the throat; as a rule, the lower jaw is without teeth. 
The eggs (Fig. 243, ¢) are deposited in jelly-like masses 
in some pool ; in two weeks, more or less, the young ap- 
pear, those of American toads being darker than those 
of frogs. They now cling to the weed by little suckers 
near the mouth parts, 1; branching tufts now appear on 
each side of the head—these are the gills, 2; the mouth 
soon appears, the tufted gills are absorbed, and we have 
the tadpole with six fish-like gill-slits. The legs are now 
seen, 4, first appearing as little bumps under the skin, 
and finally we have an animal resembling a lizard, with 
four legs and a long tail, 5 ; the latter is gradually ab- 
sorbed, 6; and the toad or frog crawls upon the shore in 
perfect form, 7. 
