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these outgrowths are of much use in breathing, but they can be 

 distended with air so as to swell out the body. This may be a 

 protective arrangement. 



Nearly fifty species of Chameleon are known, of which the 

 vast majority are natives of Africa and Madagascar, though 



Fig. 143. — Common Chameleon [Chamcsho vulgaris) 



outlying members of the group are found in Arabia, India, 

 and Ceylon, while one species, the Common Chameleon 

 {Chamceleo vulgaris) (fig. 143), ranges round the eastern and 

 southern shores of the Mediterranean, and also extends into the 

 south of Spain. 



Order 4. — Snakes (Ophidia) 



Although at first sight there seems to be a great deal of 

 difference between snakes and lizards, careful examination 

 shows that there are important points of resemblance, and 

 some zoologists include the two groups in a single order, 

 Sqttamata, among the distinctive features of which are the 

 possession of well-marked overlapping scales, a transverse cloacal 

 opening, quadrate bone movably attached to the skull so as to 

 give a double jaw-joint, and simple lungs. 



