556 CHAMELEON. FAMILY GECKOTID^. 



their position, in proportion to the amount of blood which is 

 thrown into them, and thus bring the different colours into view. 

 The change generally takes place either in consequence of vari- 

 ations in the temperature, or the amount of light to which the 

 animal is exposed, or from its being irritated or alarmed ; and 

 any of these causes may be sufficient to influence the cutaneous 

 circulation. These curious animals are arboreal in their habits ; 

 traversing the twigs and branches in a slow and cautious man- 

 ner, with the aid of the grasping powers of the feet and tail ; 

 and occasionally darting out their tongues at insects that come 

 within their reach, with such rapidity that the movement is 

 scarcely perceptible. They are very inanimate in their appear- 

 ance, often remaining in precisely the same position for many 

 hours together ; and they can exist for several months without 

 food. The lungs are large, and are connected (as in Birds) with 

 air-cells that lie among the muscles and beneath the skin ; hence 

 the appearance of the animal varies greatly, according as these 

 cavities are full or empty, being sometimes full and bloated. 

 and the next minute lean and shrunken. 



493. The GECKOTID^, or Geckos, are Lizards of small size, 

 but of repulsive aspect ; their bodies being flattened, and their 



colour lurid. Many of the species are considered as poisonous 

 by the inhabitants of the countries in which they are found ; 

 and some even assert that they infect every substance over which 

 they walk ; but both these opinions are, to say the least, very 



