44 



Vertebrata. 



as do many other genera. The geckos of India are 

 remarkable for the suckers which they bear on the 

 ends of their fingers, whereby they can walk up per- 

 pendicular walls and along ceilings. The last group of 

 lizards, the chameleons, are interesting for their 

 proverbial quality of changing colour, due to the ex- 

 pansion and contraction of certain pigment-bearing 

 connective tissue bodies in the skin. They also 



FIG. 18. 



Head of chameleon, with protruded tongue. 



possess circular eyelids, and a very long tongue (tig. 

 1 8) capable of being protruded with lightning-like 

 rapidity. 



25, Order 2, Ophidia (Snakes). These dreaded 

 animals may be regarded in some respects as special 

 modifications of the lizard type. They are scale-clad 

 and limbless, not having even a remnant of the 

 shoulder girdle persistent. The sternum and sternal 

 apparatus have also vanished, and the skeleton consists 

 of a long vertebral column, often of several hundred 

 joints or vertebrae, each of which bears two ribs, one 

 on each side. 



