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MANUAL OF ZOOLOGY. 



running on the smoothest surfaces, or suspending itself back- 

 downwards. They feed on insects, and are found in abun- 

 dance in the warmer parts of both the Old and New 

 Worlds. 



Another remarkable family of Lacertilians is that of the 



Fig. 305. Head of Gecko stentor. (After Giinther.) 



Chamceleontidtz, containing, among other species, the familiar 

 little Cham&leo Africanus, which occurs abundantly in the 

 north of Africa and in Egypt, and is so well known for its 

 power of changing its colour under irritation or excitement. 

 In this genus the eye (fig. 306) is of large size, and is covered 



Fig. 306. Head of a Chameleon (C. Petersii). (After Gray.) 



by a single circular lid, perforated centrally by a small aperture, 

 by which the rays of light reach the pupil. The Chameleon 



