126 DIVISION I. VERTEBRAL ANIMALS.—CLASS III. REPTILIA. 
original of the flying serpents of the ancient mythology. Here also is 
found the Marblet, which, having a voluminous lung that fills nearly the 
whole body, changes the hues of its skin, when excited, like the chameleon. 
Tue Fourtu FaMity orf Saurtans is composed of the Geckotians, 
small animals of nocturnal habits and disagreeable aspect, bearing a consid- 
erable resemblance to toads and salamanders. Their feet are so constructed 
that they adhere to surfaces, and enable the animal to walk on ceilings. 
They belong to the Old World. 
Tue Friern Famity consists of the Chameleons. These singular ani- 
mals are about fifteen inches in length: they live on trees, subsisting on 
insects, which they dexterously capture with their long, extensile tongue, 
that moves with great celerity. The end of this organ is furnished with a 
glutinous substance, which attracts numerous small insects, and holds them 
fast. till they are conveyed to the mouth and swallowed, when the curiously- 
armed tongue again darts forth for another batch of victims. 
The lung of the Chameleon is so vast that, when inflated, the body ap- 
pears transparent, which led the ancients to believe that these animals fed 
on air. The singular power they possess of changing their color according 
to their wants and passions, is also to be attributed to this magnitude of the 
lung. Another remarkable peculiarity of this reptile is the want of sym- 
pathy between the two sides of the whole body, each side having movements 
and affections of its own, like a separate animal. Thus, while one side may 
be asleep, the other may be awake ; one may be of one color, and the other 
of another; the eyes, too, have separate movements, and the limbs will not 
act in concert ; consequently the animal cannot swim. 
Tur Sixtm Famriy comprises the Sczndoidiens, which are recognized 
by the shortness of their feet, the non-extensibility of the tongue, and the 
equality of the tile-like scales which cover the whole body and tail. In the 
whole family there is a general approach to the serpent form. — It is divided 
into five genera, viz., the Scinques, the Seps, the Dipodes, the Chal- 
cides, and the Chirotes, all of which exhibit the same gradual descent to 
the serpent character. 
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ORDER III. OPHIDIA (Serpents). 
The first family of Serpents retains the skull, teeth, and tongue of one 
of the preceding groups, — the Seps, — and might be designated as Sauri- 
ans without feet. The Double Marcheurs (Ophidians that can progress 
either head or tail foremost), the Amphisbenes, the Typhlops, the Moles, 
which comprise the first part of the second fiuily of Serpents, also show 
