30 NATURAL HISTORY. [UPPER FLOOR. 
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 Zonuridce (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 
scales. Some have four distinct* moderately long legs, 
and exposed ears. The African Lizards of this group 
are distinguished by their thighs being marked with a 
line of pores on the under side. In Zonurus * the tail is 
furnished with spinose scales; in the Cicigna these scales 
are smooth. The American species* ( Gerrhonotus,') on the 
contrary* have no glands under the thighs, and the scales 
of the tail are smooth. 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 
drum 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 ( Chirocolidce) the scales 
of the tail are placed in rings alternating with each other. 
The family of Chamcesauridce (Case 5) have only rudi¬ 
mentary limbs* and all the scales of the body are elongate* 
keeled, and placed in longitudinal series. 
The family of Seines ( Scincidce * Case 5) have a shielded 
