214 BACKBONED ANIMALS. 
and the head ornamented with spikes. They run with 
great rapidity, and so resemble the dry ground that they 
Fic. 256.—The Ameri- 
can chameleon (Azo- 
lis princepalis), 
are indistinguishable a 
few feet away. They 
live upon insects, and 
are easily domesticated. 
Allied to the iguanas is 
the great sea-lizard of 
the Galapagos Islands. 
They attain a length of four 
feet. Their tails are flattened 
and their feet partly webbed. They 
take to the water readily, living upon 
sea-weed. A land species lives in 
burrows. 
The Wall-Lizards (Geckoit- 
de)* are short, flattened, and slow 
* The middle of each caudal vertebra 
has a thin cartilaginous partition. At this 
point the tail is often broken, and eventu- 
ally renewed, sometimes two tails growing. 
According to Gunther, they are enabled to 
throw off their tails spontaneously when pursued, the wriggling offcast 
attracting the attention of the pursuer, while the gecko escapes. They 
