ROOM X.] NATURAL HISTORY. 29 
of a lanceolate form, besides which, the male has two 
spiniform 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 reproducing 
their tails when broken off, an accident which often hap¬ 
pens in the mere exertion of the animal to escape from 
danger. The reproduced part has only a central cartilage 
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 be¬ 
comes forked. A specimen of a Lizard with such a tail, 
may be seen in this Case. 
The family of Zonuridce (Case 3) are very like the true 
lizards, but the back and belly are covered with large squarish 
shields, and the sides, which are only dilated when the ani¬ 
mal has eaten a full meal, are covered with small scales. 
Some have four distinct, moderately long legs, and ex¬ 
posed ears. The African Lizards of this group are dis¬ 
tinguished by their thighs being marked with a line of 
pores on the under side. In Zonurus , the tail is furnished 
with armed scales; in the Cicigna these scales are un¬ 
armed. The American species, ( Gerrhonotus ,) on the 
contrary, have no glands under the thighs, and the scales 
of the tail are not armed. The Scheltopusiks ( Pseudopi ) 
of Europe, have only rudiments of legs, in the form of 
undivided lobes, placed on the side of the vent; and the 
Glass Snakes of North America ( Ophisauri ) are quite des¬ 
titute of legs : all the^ species of these genera have the 
tympanum of the ear exposed. 
The CercosauridcE (Case 3) are long cylindrical rep¬ 
tiles, with rounded sides, covered like their backs with 
square scales placed in cross series. The scales of the 
tail are keeled, and placed in longitudinal series, as Cer- 
cosaurus , while in the next family (C hirocolidce) the scales 
of the tail are placed in rings alternating with each other. 
