34 
NATURAL HISTORY. [UPPER FLOOR. 
Monitor, is probably to be traced to that origin. The 
Americans have a similar idea with regard to the Safe¬ 
guards ( Teius ) of the New world. In the Collection are 
the Double-crested Ada ( Teius bicarinatus), very like the 
Crocodile in shape; the Variegated Safeguard ( Teius 
monitor ) ; various species of Ameiva ( Lacerta ameiva , 
Lin.) : and the Intermediate Centropyx (Teius intermedins ), 
remarkable for having lanceolate abdominal plates, and, the 
males, two spiniform scales on each side of the base of the 
tail. Next follow the True Lizards, which, like the Moni¬ 
tors, are peculiar to the Old world ; but they are at once 
distinguished from them by their tongue being, like those 
of the Safeguards, simply contractile, whereas that of the 
Monitor is withdrawn into a sheath under the gullet when 
at rest, in the same manner as the tongue of snakes. The 
Collection contains several specimens of this genus, most of 
which are found in Europe ; as the Ocellated Lizard (Lac. 
ocellata ), Green Lizard (Lac. viridis ), and the Wall 
Lizard (Lac. muralis ), found on heaths near London. 
This animal is said to be both oviparous and viviparous, 
and has been confounded by authors with another species 
(Lacerta agilis ), not a native of Britain. Lastly, the 
Swift Lizards (Tackydromns), which very much resemble 
the true Lizards, but have an exceedingly long body and 
tail, with their fore and hind legs very far apart, and the 
back covered with shields somewhat like those on the 
belly. They are found in China and Java, and are said to 
run with amazing velocity. Most of these animals have the 
faculty of reproducing their tails when broken off, an ac¬ 
cident which often happens in the mere exertion of the 
animal to escape. 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 mem¬ 
ber becomes forked. A specimen of a Lizard with such a 
tail, may be seen in this Case. 
Cases 3 and 4 contain those Saurian Reptiles which 
have short contractile tongues, slightly notched at the end. 
The first of these are the Guanas, which have their 
teeth attached to the inner edge of the jaw-bone, and mostly 
lobed and indented. They are all found in America. 
