ROOM X.] NATURAL HISTORY. 25 
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 Telus , 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 
are peculiar to the Old World, chiefly differ from the former 
in their eyelids being protected by a bony plate. Many 
species are found in Europe. One species, Zootoca crocea , 
found on our heaths, is said to hatch its young in the 
body of the mother, if it be kept in a dry place; but to 
deposit eggs, if in a moist one. 
Most of these animals have the faculty of forming a 
new tail when it has been broken' off, an accident which 
often happens in the mere exertion of the animal to escape 
from danger. The new formed tail has only a central car¬ 
tilage in the place of the bones, and is often covered with 
scales, different from those of the rest of the tail. If the 
tail be cracked only on one side, and not thrown off, a new 
tail often springs out of the crack, so that the member 
becomes forked. A specimen of a Lizard with such a 
tail, may be seen in this Case. 
The family of Zonundce (Case 3) are very like the true 
lizards, but the back and belly are covered with large nearly 
square shields, and the sides, which are only dilated when 
the animal has eaten a full meal, are covered with small 
c 
