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INTRODUCTION TO ZOOLOGY. 



The genus which comprises the greatest number of species 

 is that of the Iguanas (Fig. 227), which are found only in 



Fig. 227. IGUANA. 



the New World. Some of these are so much as five feet in 

 length, and the colour a beautiful green of a variety of shades. 

 They have a singular crest along the back, and a hanging 

 pouch, like the dewlap of oxen, under the chin. This pouch 

 they have the power of inflating with air. They live among 

 the branches of trees, and feed principally, but not exclu- 

 sively, upon leaves and fruits. Eggs and insects form a por- 

 tion of their diet.* 



Darker in colour and more repulsive in aspect are the 



Fig. 228. GKCKO. 



Geckos (Fig. 228) or Nocturnal Lizards. " Though timid 

 and harmless, they are always regarded by the vulgar as 



* A gigantic fossil reptile discovered in the South of England, in 1834, 

 by Dr. Mantcll, is named the Iguanodon, from its resemblance in many 

 points of structure to the Iguana. 



