LUNGS AND AIR SACS 



If all this fails and the enemy is not to be daunted by 

 bluff, the chamaeleon relies upon its scragginess in this 

 way. Its lean sides, like those of a tiger, can by con- 

 traction of the muscles lying between the ribs become 

 still more attenuated. This accomplished, the chamae- 

 leon prudently, but in another sense to the usual one, 

 turns its back upon its foe, and remains perfectly quiet. 

 The leanness reduces its dimensions to those of a straight 

 line, which has no breadth, and seen in profile, the cham- 

 aeleon escapes unwelcome attention. Viewed internally, 

 the chamaeleon is quite as different from its Lacertilian 

 relatives as it is externally. The most prominent fea- 

 ture revealed by the dissecting knife is the curious tags 

 or blind outgrowths of the lungs, which spread through 

 the body and permit the animal to " visibly swell," as 

 has been already pointed out, when its emotions are 

 roused. That the lungs should have these connected 

 sacs, which do not perform a respiratory function at all, 

 for they have no blood-vessels, is a point of approxima- 

 tion to the air sacs of birds ; and constantly in consider- 

 ing the structure of reptiles do we come across points of 

 resemblance to their really near, but apparently so 

 widely different, fellow-countrymen the birds. We 

 have spoken hitherto of the chamaeleon ; but in truth, 

 there are very many different kinds of chamaeleons, 

 though the remarks made in the foregoing lines apply, 

 with the exception of a few points, to all of them. There 

 are at least sixty species of chamaeleons which exist only 

 in the Old World, and in that hemisphere live mostly in 

 Africa and Madagascar. 



As they have all the same kind of habits the differences 

 between the various species are not very striking, except 

 for a half a dozen or so of species which belong to two 

 separate genera known as Brookesia and Rhamphokon, 

 which have the merest stumpy apology for a tail. The 

 difference is quite analogous to the long and prehensile 



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