+ 
“~ 
BONGS AN DAK SACS 
If all this fails and the enemy is not to be daunted by 
bluff, the chameleon 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 chamz- 
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- 
eleon escapes unwelcome attention. Viewed internally, 
the chameleon 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 chameleon ; but in truth, 
there are very many different kinds of chameleons, 
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 chameleons 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 Rhampholeon, 
which have the merest stumpy apology for a tail. The 
difference is quite analogous to the long and prehensile 
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