REPTILES. 197 
Monkeys use theirs (§ 53). Its movements are slow. 
No part of it moves quickly but its tongue. This is a 
singular instrument. It is a long hollow tube with a 
swollen fleshy extremity, which is always covered with a 
glutinous substance. In catching insects it is darted out 
and returned into the mouth with a velocity which al- 
most eludes the eye, the glutinous secretion making the 
insect to adhere to the tongue. The eyes of the Chame- 
leon can be moved independently of each other, which 
gives the animal a strange aspect, one eye, perhaps, be- 
ing directed forward, while the other is directed back- 
ward. The skin is covered with horny granulations. 
The changeableness of the color of the skin has been ex- 
aggerated ; still, the change is perceptible through vari- 
ous shades from light to dark, owing to changes in the 
arrangement of the granules in the skin, and in the amount 
of blood inthem. The lungs are large, and there are air- 
sacs connected with them in various parts of the body. 
When these are full of air the animal looks bloated, but 
the next minute it may appear lean and shrunken, having 
emptied these sacs. The story that the Chameleon lives 
on air gained currency partly from this circumstance, 
and partly from the almost invisible quickness of motion 
of the tongue, really invisible to the careless observer. 
The common Chameleon, Fig. 159, abounds in Northern 
Africa, the south of Spain, and Sicily. 
Fig. 159.—Chameleon. 
