ROOM X.] NATURAL HISTORY. 31 
The Gavials agree with the Crocodiles in regard to their 
teeth, but differ by the muzzle being very long and slender. 
Specimens of all the three genera are in the Collection. 
The upper jaw of these animals is generally, but erroneously, 
said to be moveable ; the mistake having arisen from the 
lower jaw being much produced posteriorly. 
Case 2 contains those Saurian Reptiles which have the 
tongue long and deeply forked; namely, the Monitors of 
the Old world and its islands. Among these are the Two- 
banded Monitor (Mon. blmttatus), from India; the Laced 
Monitor [Mon. varius), from New Holland ; the Orna¬ 
mented Monitor (Mon. ornatus), from the Cape; and the 
Grey Ouran (Mon, seme us), from Egypt. All these speci¬ 
mens live near the water’s edge, and are venerated by the 
natives, who assert that they give notice of the approach 
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 
Americans have a similar idea with regard to the Safe¬ 
guards (Telus') of the New world. In the Collection are 
the Double-crested Ada (Telus blcarlnatus ), very like the 
Crocodile in shape; the Variegated Safeguard (Telus 
monitor ); various species of Ameiva (Lacerta ameiva, 
Lin.) ; and the Intermediate Centropyx ( Jems Intermedins ), 
remarkable for its lanceolate abdominal plates, besides which, 
the male has two spiniform scales on each side of the base of 
the tail. Next follow the True Lizards, which, like the Mo¬ 
nitors, are peculiar to the Old world ; but they are at once 
distinguished from them by the 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Monitor is withdrawn into a sheath under the gullet when 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 (Tacliydromus), 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 ab- 
