186 ANIMAL FORMS 
forms and sizes, always of definite arrangement, cover the 
body. The scales are always colored, in some species as 
brilliantly as the feathers of birds, and usually harmonize 
with the surroundings of the animal, enabling it to escape 
the attacks of its many enemies. Altogether the lizards 
are a very attractive group of animals. As in the salaman- 
ders, the vertebral column is usually of considerable length, 
but it too presents a lighter appearance and a greater flexi- 
bility. Slender ribs are present, and a breast-bone and the 
girdles which support the limbs. Although more ossified 
than in the amphibians, the skull still continues to be com- 
posed here and there of cartilage. The roof also is yet 
incomplete, but with the firm plates on the surface of the 
head ample protection is afforded the small brain under- 
neath. As above mentioned, the limbs are slender and 
insufficient to support the body, which accordingly rests 
upon the ground, and by its wrigglings and the pushing of 
the limbs is borne from place to place. It will be recalled 
that some of the salamanders living in subterranean haunts 
and burrowing in the soil have no need of limbs, and the 
latter have accordingly disappeared. This condition is 
paralleled by certain species of lizards. The blindworms 
(which are neither blind nor worms, but true lizards, though 
snake-like in appearance) are devoid of limbs, as are also 
the “ glass-snakes.” In some species the hinder pair arise 
in early life, but they remain small, and ultimately disap- 
pear. In almost all lizards the tail is very brittle, breaking 
at a slight touch. In such case the lost member will grow 
again after a time. 
177. The snakes (Serpentes).—The snakes are character- 
ized by a cylindrical, generally greatly elongated body, in 
which the divisions into head, neck, trunk, and tail are not 
sharply defined. As we have seen, this is also true of cer- 
tain lizards, but the naturalist finds no difficulty in detecting 
the differences between them. Another peculiarity of the 
snakes is in the great freedom of movement of the bones 
