NATURAL HISTORY. 
33 
ROOM X.] 
genus there are many species.—Lastly, the marbled Lizards 
(Polychrus) have neither dilated toes nor any dorsal 
crest. 
Case 4 contains the Geckos, nocturnal Lizards, of a dull, 
lurid appearance, with depressed heads,and large round eyes. 
Their body is usually covered with small scales, amongst 
which are frequently larger tubercles ; and the under side of 
their toes is generally furnished with variously shaped, im¬ 
bricated scales, or folds of the skin, which enable the animal 
to crawl up glass, and even to run with facility, the back 
downwards, on the ceiling of a room, like a fly. They are 
found in all parts of the world, and are divided into many 
groups, according to the form of their toes. Some of the 
most peculiar are the Common Gecko ( Gecko gultatus), 
from India * the Chinese Gecko ( Gecko Revesii), from 
China ; and the Ornamented Gecko ( Gecko ornatus ), from 
the Isle of France. All these have only a single trans¬ 
verse series of scales, on the under side of each toe. Hard- 
wicke’s Gecko ( Eublepharis Hardwickii) differs from the 
former, by the toes being more slender, and less dilated; 
one of the species, Horsfield’s Gecko ( Pteropleura Hors- 
JLeldii) which lives in the ponds in Java, has the skin on 
the side of the chin, body, limbs and tail dilated into a 
kind of fin. 
Many of the species of these Lizards, from their lurid 
appearance, are considered as poisonous by the natives of 
India, and some even assert that they infect every sub¬ 
stance which they walk over, but this is, at least, ex¬ 
tremely doubtful. 
Other species have the scales under the toes divided by 
a central groove, into which the claws are retractile ( The- 
cadactyl-i). One of these, the Smooth Sheath-claw (Gecko 
Icevis), has many scales under the toes, and on being 
caught, the animal, in its exertion to escape, often casts of 
its tail. It does the same if thrown alive into spirits, in 
which case the separated tail contracts, and assumes an 
almost globular shape, and is most usually found in this 
state in collections, whence this species has been generally 
called the Turnip-tail Gecko ( Gecko rapicauda). The 
Beautiful Sheath-claw ( Vhyllodactylus pulchellus ) has only 
two or three transverse scales on each side of the claws, so 
c 3 
