556 FAMILY CHAMELEONIDJE, OR CHAMELEONS. 



492. The family CHAMELEONIDJE, or Chameleons, is dis- 

 tributed through the warmer parts of the Old World, but not in 

 America. The species it includes are distinguished from all 

 others, by several very remarkable peculiarities. Their bodies 

 are much compressed, or flattened sideways ; and the back is 

 surmounted by a sharp ridge. Two of the toes are directed 

 backwards, opposing the three anterior ones, and thus forming 

 very efficient instruments of prehension. The tail also, which 

 is of a tapering form, is prehensile. The tongue is a hollow 



FIG. 330 CHAMELEON. 



tube, with a swollen fleshy extremity ; and it is capable of being 

 darted out instantaneously to a great distance, and of being as 

 rapidly drawn in. This organ is furnished with a glutinous 

 saliva ; by which the insect prey, that serve for the support of 

 these extraordinary Reptiles, are attached to it. The eyes of 

 the Chameleon are capable of being moved independently of each 

 other ; and they are constantly covered with a sort of eyelid, 

 in which there is a small aperture corresponding with the pupil. 

 Its skin is not furnished with scales, but is beset with horny 

 granules. It undergoes, as is well known, remarkable changes 

 of colour; varying through different shades of yellow, red, 

 gray, brown, violet, and dull inky blue. The cause of these 

 changes is not well understood ; by M. Milne Edwards, they are 

 referred to two differently coloured layers of pigment, which are 

 stated by him to be so arranged, that either of them may be 

 made to appear alone under the cuticle, or the two may be 

 presented in different degrees of combination. It is not easy 



