ADAPTATIONS 



97 



did so, although probably not so frequently or so persistently 

 as the iguanodon. 



The flying type is only properly developed in the extinct 

 pterodactyles, or Ornithosauria. The so-called flying dragons 

 (a name much more appropriate to the pterodactyles) constitut- 

 ing the genus Draco and belonging to the lizard family Agamidce 



Fig. 4. — Restoration of the Iguanodon. 



have, however, acquired a kind of spurious flight, or rather are 

 capable of taking flying leaps by means of a parachute-like ex- 

 pansion of the skin of the sides of the body. The depressed 

 form of the body in the flying dragons shows that these lizards 

 have been evolved from an ordinary arboreal member of the 

 Agamidce by an ultra-development of a membranous expansion 

 of the skin of the sides of the body similar to that found in the 

 fringed gecko. In the "dragons" the wing-like parachute of 

 each side is supported by an outward extension of four or five 

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