32 
Lizards. 
■REPTILES. Tiuck-tonoukd Lizards. 
si)ines. It is of a depressed form ; the head is small 
and furnished with two or three veiy large spines over 
the eyebrows. “ The external apjiearance of this 
lizard,” says Dr. Gray, who first made it known, “ is 
the most ferocious of any that I know, the horns of the 
head and the numerous spines on the body giving it a 
most formidable aspect.” “ I have named this genus,” 
he adds, “ from its appearance, after ‘ Holoch^ horrid 
king.’ ” These animals are highly coloured, especially 
on the under surfaces, which are covered with black- 
edged dark red spots. We do not know their habits, 
but they are harmless enough. 
Tribe III. — DENDROSAURA. 
The third tribe of Thick tongued Lizards, and the 
last of the Saurian reptiles, is that of the Tree Lizards 
{Dendrosmtra).* In this tribe the scales of the belly, 
sides, and back are gi-annlar merely, and di.sposed in 
circular bands. The toes are five in number on each 
foot, and disposed in two groups, which are opjiosed to 
each other, and admirably adapted for grasping the 
branches of trees, &c. 
This tribe contains only one family, that of the 
CiiAJtELEONS {Chameleonidai ) ; and this family consists 
of only one genus (C'/<a?nefeo),f and eighteen sjiecies. 
They are all natives of the Old World, being confined 
to Africa and Asia, though one of them has become 
naturalized in Southern Europe. 
The Chameleons are truly singular animals, whether 
we regard their internal or their external structure. 
They dilfer so much from all other Saurians, that 
Dumeril and Bihron place the famil}' in a section 
by themselves between the crocodiles and lizards. 
“ These animals,” say these authors, “ have such a 
bizarre structure, and so dilferent from that of all 
other reptiles, that it is almost necessary to separate 
them from the rest of the Saurians. It is with difficulty 
we can observe even the slightest analogy between any 
species of Chameleon and any other lizard, whether 
we look at the granular and variable disposition of the 
integuments, or at ihe arrangement of the different 
jiortions of the skeleton. In fact, none of them have 
the slightest relation, either in the form and move- 
ments of the tongue, or in the structure and mode of 
articulation of the limbs, or, lastly, in the conforma- 
tion and uses of the tail.” In Dr. Gray’s arrange- 
ment, however, they close the series of the Lizards, 
and this seems to be their true position. The essential 
characters which separate the Chameleons from all the 
other families of the Saurians are three : — 1st. The 
existence of a cyclindrical, worm-like, very long tongue, 
which is terminated by a smooth, ileshy tubercle, lubri- 
cated by a viscid saliva. 2nd. Their having their five 
toes, in each foot, connected together as far as their 
last joint, but divided into two unequal sets, three in 
one and two in the other. 3rd. Their body being 
compressed, covererl with a shagreened skin, and their 
tail being conical and prehensile. 
* P’rom the two Greek words, detulron a tree, and 
saurn (iraufai, a lizard. 
t Eroni the Greek word chamaileon a little 
lion. 
The integuments of the Chameleons are destitute of 
true scales ; the skin is rugose, tubercular, and finely 
shagreened by unequal projecting granules, which are 
dLstributed in symmetrical groups. It appears veiy 
loose, adhering seemingly to the muscles only on the 
head, back, the free extremity of the tail, and the feet. 
Besides this, throughout its whole extent, numerous 
vacancies or free spaces are left, into which the air 
from the lungs c.an penetrate, so as to inflate it. In 
this skin there exist two layers — 1st. A mucous tissue 
variously coloured by a pigment ivhieh appears to be 
gifted with a jieculiar chromatic property; and 2nd. 
A true transparent epidermis which forms a continued 
layer, and moulds itself most exactly upon all the 
inequalities of the surface. The body is compressed or 
flattened sidewise, from right to left, and surmounted 
on the back by a projeciing sharp ridge, a similar one 
being seen also in some sjiccies along the belly. Their 
legs are slender, elevated, and much longer in projior- 
tion than those of any other reptile, so that they can 
raise the body so high, that their belly never rests upon 
the surfaces upon which thej' walk or climb. The 
tail is rather long, of a conical shape, and like that 
organ in some of the monkey tribe is prehensile ; that 
is, capable of twisting itself round, and grasping the 
various substances upon which they move. The striic 
ture of this organ and that of their feet fenders those 
animals truly arboreal in their habits. The toes, as 
we have mentioned above, are divided into tw'o sets, 
three on one side and two on the other, and these are 
disposed inversely; that is, the set containing tw’o toes 
is placed externally on the fore feet, and the set con- 
taining three is placed externally on the hind feet. 
I'hese two parcels of toes are opposed to each other, 
and thus form regular pincers, by means of which they 
can firmly grasp and retain hold of the branches of trees, 
upon w'hich they live. The head of the Chameleons is 
very large and generally more or less strongly ridged, 
and tlie neck is so short that the head appears to rest 
U])un the shoulders. There is no external ear apparent, 
these organs being hidden under the skin. The orbits 
are very largo, and the eyes are particularly prominent, 
the globe being in a great measure situated outside 
the cavity. The whole of this organ is covered with a 
single eyelid, which is a continuity of the skin of the 
head, and is pierced with a small dilatable hole in the 
centre, forming, in fact, a true external pupil, which 
the animal can dilate or close at will. It can even 
vary the shape of the opening, for we see it sometimes 
become transverse or vertical. From the peculiar 
arrangement of the nerves and muscles, each of the 
eyes can move independent of the other. They can 
move in dilferent directions, one upwards, the other 
downwards ; the one foiwvards, the other backwards ; 
and in all sorts of ways, without the head undergoing 
any change of position. “ You cannot tell,” says Mr. 
Gosse, “ whether the creature is looking at you or not ; 
he seems to be taking what may be called a (jeneral 
view of things; looking at nothing particular, or 
rather, to save time, looking at several things at once. 
Perhaps both eyes are gazing upwards at your face ; a 
leaf quivers behind his head, and in a moment one eye 
timis round towards the object, while the other retains 
