- REPTILIA. 279 
ribs do not support the membrane—the animal is enabled to glide in safety 
for a considerable distance through the air. The best known species is D. 
dandini, or flying dragon of Java (pl. 81, fig. 33, and pl. 89, fig. 3). The 
genus Agama (pl. T4, fig. TT) was formerly made to include the North 
American Tropidolepis and Phrynosoma. As restricted it now includes 
no American species. Stellio (pl. 74, fig. T8) contains the only European re- 
presentatives of the Jewanida, S. vulgaris. 
Fam. 5. Chameleontide (the chameleons). This family, contaiming but. 
a single genus, Chameleo, with 14 or 15 species, is separated by the most 
strikingly marked characters from all the other divisions of the Saurian 
order. The first peculiarity of the’ chameleons consists in the absence of 
scales. . The skin, however, unlike that of the Batrachia, is dry, and 
supplied with fine granulations of unequal size but of symmetrical distri- 
bution. The body is much compressed, so much so that the back and 
belly, in some cases, appear provided with crests. The feet, longer in 
proportion than those of any other saurian, are provided with five toes 
each, arranged in two sets, one including two and the other three. In the 
fore feet, the binary packet is exterior, the opposite being the case in the 
posterior extremities. In fact, the toes are all united together as far as the 
claws by the skin, and this then appears divided between the second and 
third, or between the third and fourth toes. The head is large, and, owing 
to the shortness of the neck, appears to rest on the shoulders. ‘The orbits 
are very large, and the eyes are covered by a single annular pupil, with a 
dilatable central aperture. Either eye can be moved separately, and the 
two may be looking in entirely opposite directions at the same time. 
There is no external meatus auditorius. The mouth opens beyond the 
eyes, and is provided with trilobed cutting teeth, arranged in a single series 
along the sharp edges of the two jaws. <A highly curious feature is to be 
found in the tongue, which, when at rest, appears like a fleshy tubercle, 
capable, however, of being suddenly protruded to a distance equal to the 
length of the body. The tip of the tongue is covered with a sticky secre- 
tion, by means of which small insects are secured. The tail is prehensile, 
and like that of the American monkeys can be used as an instrument of 
progression. The chameleons are especially arboreal, a condition of life 
for which they are well fitted by reason of the opposable divisions of the 
feet and the prehensile tail. Their motions are exceedingly slow, and 
when stealing on their prey (minute insects) almost imperceptible. When 
arrived within a proper distance of the object of their pursuit, the tongue 
is protruded with inconceivable velocity, and retracted almost as quickly. 
The changes of color experienced by the skin of the chameleon have made 
it an object of curiosity from the most remote time. Highly exaggerated 
notices of this phenomenon are to be found in the writings of many of the 
ancients ; more recent investigations, however, have dispelled much of the 
fable attaching to this curious animal. A change of color, under different 
circumstances, is not peculiar to the chameleon, but is exhibited by many 
of the tree-frogs, and in fact by most of the anourous batrachia. In all, it 
appears to depend, in some obscure way, upon the loose attachment of the 
483 
