LIZARDS 



235 



so that the superior pressure of the external air presses the foot against 

 the object with which it happens to be in contact. (Compare the 

 suctorial discs of the cuttle-fish.) 



A still more remarkable group are the so-called " flying lizards." 

 The most familiar of these is the Flying" Dragon (Draco volans) of the 

 Sunda Islands. It lives in the densely-foliaged crowns of trees, and, 

 like the birds of the tropical zone, is resplendent in all the colours of the 

 rainbow. (What is the significance of this brilliancy of colour ? Com- 

 pare with parrot and humming-bird.) The animal is about 8 inches 

 long, and on each side of the body possesses a parachute-like expansion 

 formed by a fold of the integument and supported by ribs growing 

 straight out from the spinal column through the body waifs. By means 

 of these parachutes the animal can swing itself obliquely from above 

 downwards (why not in the opposite direction ?) from branch to branch, a 

 mode of locomotion which forms an excellent aid to it in the pursuit of 

 insects. 



Another peculiar member of this order is the Chameleon (Chamceleo 

 vulgar is). This animal is a native of Southern Spain and North Africa, 

 and reaches a length of about 12 inches. It is truly arboreal in habit, 

 and on account of its variable colour is almost totally indistinguishable 

 amid dense foliage. Its colour is subject to all sorts of changes, passing 

 from green into blue, gray, brown, black, and all sorts of intermediate 

 tints and combinations, as a result either of differences in the reflection 

 of light, or of hunger, thirst, etc. (see p. 253, Section d). Indeed, the 

 animal frequently bears more resemblance to some gnarled excrescence 

 than to a living creature. The toes are perfectly adapted for climbing, 

 being arranged, not side by side, but opposite each other (three against 

 two), so as to form tongs for clasping and holding on to objects. (Com- 

 pare with scansorial birds.) The legs are long, so that they can be 

 placed one behind the other when the animal is clinging to a branch. 

 (Compare, on the other hand, the sand lizard.) The long prehensile tail 

 (compare with howling monkeys) acts as a fifth hand, as it were, and 

 lends additional support to the animal's high and laterally compressed 

 body. Clinging in this manner the animal will remain for days, motion- 

 less upon a branch, looking out for prey (insects). The eyes are spherical 

 and covered with a single lid, perforated centrally by a circular opening 

 in front of the pupil. These eyes can be moved quite independently of 

 each other, so that the animal can look simultaneously in front and 

 behind it, above and below, and is thus able to survey a large space in 

 search of food. Being, however, extremely slow in its movements, the 

 chameleon would have long to wait before it could capture a fly, beetle, 

 or butterfly if its tongue did not provide it with a most singular instru- 



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