\ O j 
ROOM X.] NATURAL HISTORY. 29 
I. The Scaly Reptiles (Squamata) have their bodies co¬ 
vered with overlapping scales,, the skull formed of separate 
bones, and the ear bones are external, and only arti¬ 
culated to the rest; their vent is a cross slit, and the ge¬ 
nerative organs are bifid. \ They consist of the Saurian 
Reptiles or Lizards, and Ophidian Reptiles or Snakes. 
The Saurian Reptiles ( Sauna ) are generally provided 
with four limbs, but in some the limbs are in such a rudi¬ 
mentary state, as to be hidden under the skin. The jaw 
bones are united together in front, for as these animals 
live on insects, fruits, &c., which they reduce by chewing, 
they are not required to dilate their mouths for the swallow¬ 
ing of large masses, as is the case in the snakes. 
The family of Monitors ( Monitoridce , Case 3,) have a 
long deeply forked tongue, which, like that of the snakes, 
is capable of being withdrawn into a sheath placed at its 
base, and the head, body and limbs are covered with small 
scales. They are only found in the warmer parts of the 
Old World, living near the water’s edge, and are venerated 
by the natives, who assert that they give notice of the ap¬ 
proach of the Crocodiles, by hissing when they perceive one 
of those animals. Whether this be fact or fiction, the name. 
Monitor, is probably to be traced to that origin. 
The family of Heloderms (Helodermidce) have their 
body and head covered with large convex scales. Un¬ 
like other lizards, their teeth have a groove behind, like 
the fangs of serpents; they are said to be poisonous, 
but this may be a mistake, for ignorant persons are in¬ 
clined to believe that all reptiles are dangerous. They 
come from Mexico, and having been seen in a dried state 
only, the form of their tongue is not known. 
The following lizards have an equally lengthened and 
deeply forked tongue, but it only contracts its length, 
and is not furnished with any sheath. 
The family of Safeguards, ( TeidcE , Case 3,) which 
have the head covered with large shields, and the back and 
limbs with small scales, are confined to the warmer part 
of the New World, as the genera Teius, Ameiva, and Cen - 
tropyx , differing from each other in the shape of the plates 
on the belly; the latter are remarkable for their being 
of a lanceolate form, besides which, the male has two 
spine-shaped scales on each side of the base of the tail. 
The family of true Lizards, ( Lacertidce , Case 3,) which 
