CLASS III. EEPTILIA: ORDER 3. SATJRIA. 
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togetlier by skin, that each foot maj be described as forming a hand composed of a single finger 
and thumb. By means of these grasping organs, aided by their prehensile tails, the chameleons 
climb about upon shrubs and trees in search of the insects which constitute their sole nourish- 
ment, but they exhibit none of that agility which renders many of the other small hzards such 
interesting objects. All their motions, in fact, are very slow, and give the spectator the idea of 
the most painful caution ; they are very sluggish, and sit for a long time motionless upon a 
branch, only occasionally giving a scarcely perceptible sign of life, by moving one of the eyes, 
each of these standing out and being capable of independent motion. The eyes, one often look- 
ing one way and the other in a different direction, have a most extraordinary appearance. 
At first sight it would appear that a sluggish creature like this would have but little chance 
of capturing a sufficient number of flies and other insects, the active denizens of the air, which 
constitute its only diet, to satisfy the necessities of its appetite ; but on examination we find 
that the structure of the tongue of the chameleon is admirably adapted to assist in procuring 
food. This tongue is composed of a hoUow tube, capable of extending itself with the rapidity 
of lightning to an enormous comparative length ; it is terminated by a fleshy knob, which has a 
cup-like cavity in its anterior surface, and this is always imbued with a viscid secretion. When 
the chameleon has marked an insect for its prey, it rolls about its strange looking eyeballs, and 
immediately darts the tongue at it ^vith the most astonishing rapidity, and rarely misses its aim, 
although the tongue is often protruded to more than twice the length of the whole body of the 
creature. The fly, or other insect, is of course drawn back with the tongue into the mouth. The 
difficuhy of observing processes which are eff'ected so instantaneously, coupled with the fact that 
the chameleon can support a very prolonged abstinence without injury, led the ancients to the 
opinion that this animal was nourished by air alone ; and this, which has frequently furnished 
the poet with similes, is still, to a certain extent, a matter of popular belief. 
Another curious subject connected with the chameleon, and which has also been much exag- 
gerated, is its power of changing its color. The variation in this respect appears to be that the 
animal, under certain circumstances, passes gradually from its natural pale gray color through 
pale green to yellow and dingy red ; and if the exciting cause of the change be continued, it 
will finally become dusky violet, or nearly black. The cause of this phenomenon is described as 
follows : beneath the transparent epidermis there is a great quantity of minute, soft granules, 
