OPHIDIA, 629 
The Agamas (Agamidz) are acrodont lizards common in the Eastern 
hemisphere. Examples.—4Agama; Draco, with the skin extended on 
long prolongations of five or six posterior ribs; Chlamydosaurus, an 
Australian lizard, with a large scaled frill around the neck ; Moloch, 
another Australian form bristling with sharp spikes. 
Iguanas (Iguanide) are pleurodont lizards, represented in the 
warmer parts of the New World. Examples.—/guana, an arboreal 
lizard, with a large distensible dewlap ; Amélyrhynchus or Oreocephalus 
cristatus, a marine lizard confined to the Galapagos Islands; Axo/zs, 
the American chameleon, with powers of rapid colour-change ; 
Phrynosoma, the American ‘‘horned toad,” with numerous horny 
scales, and a collar of sharp spines suggesting in miniature that of 
some of the extinct Reptiles. 
The slow-worms (Anguidze) are limbless lizards, with serpentine 
- body, long tail, rudimentary girdles and sternum. The British Anguzs 
fragzlzs is not blind or poisonous, as popularly asserted ; the tail breaks 
readily ; the young are hatched within the mother. 
The poisonous Mexican and Arizona lizards (Heloderma horridum 
and A. suspectum) are over a foot in length, and are covered with 
bead-like scales, 
The Varanide are large carnivorous forms, most at home in Africa, but 
represented also in Asia and Australia. The Monitor of the Nile, Vaxanus 
niloticus, 5 or 6 ft. long, destroys eggs and young of Crocodiles. 
The Amphisbzenide are degenerate subterranean lizards, without 
limbs, with rudimentary girdles, with no sternum, with small covered 
eyes, with hardly any scales. 
The Lacertidz are Old World pleurodont lizards, such as Pseudopus 
(Europe and 8. Asia) and Lacerta virddds, the green lizard of Jersey and 
S. Europe. 
The Chameleons (Chameleontide) are very divergent lizards, 
mostly African. There is one genus, Chameleo. The head and the 
body are compressed ; the scales are minute; the eyes are very large 
and separately movable, with circular eyelids pierced by a hole; the 
tympanum is hidden; the tongue is club-shaped and viscid; the 
digits are divided into two sets, and well adapted for prehension ; the 
tail is prehensile; the power of colour-change is remarkably 
developed. 
The Chameleons exhibit numerous anatomical peculiarities. As in 
the Amphisbeenas, there is no epipterygoid. The pterygoid does not 
directly articulate with the quadrate, which is ankylosed to the adjacent 
bones of the skull. 
Order Opuipia. Serpents or Snakes 
The elongated limbless form of snakes seems at first sight 
almost enough to define this order from other Reptiles, but 
it must be carefully noticed that there are limbless Lizards, 
limbless Amphibians, and limbless Fishes, which resemble 
snakes in shape though they are very different in internal 
