LIZARDS 
173 
t'iouo oy Saville- Kent^ f.Z.S, 
AUSTRALIAN YORK OR MOUNTAIN -DEVIL 
^ spinous liosard ivhich inhabits the arid plains of Central Australia 
emerald-green and paleFrenchgrey. Around 
the lips and eyes there are lines of brightest 
yellow, and the throat is almost pure white. 
The small group of GiRDLE-TAILED 
Lizards belongs exclusively to the African 
and Madagascan regions, its typical repre- 
sentative being the Cape and Orange River 
Colony species, illustrated on page 575. The 
symmetrical whorls of long, spinous scales 
encircling the tail in this and the allied 
forms constitute a prominent feature, and 
have originated the popular name of Cirdle- 
tails. 
The most aberrant representatives of 
the Lizard Tribe, with regard to one very 
important characteristic, are undoubtedly the 
two species of Heloderm, or “ Silatica,” as 
they are called by the natives. These reptiles 
(page 576) occupy the unenviable position of 
being the only known lizards which possess 
poisonous properties, their bite having been 
demonstrated to be fatal to smaller mammals, 
and to be attended by very serious symptoms in the case of human subjects being bitten. 
The more common Mexican Heloderm has been in residence at the Zoo for many years; it 
attains to a length of from 18 to 20 inches, and its stout, squat body, short limbs, warty skin, 
and peculiar colouring are calculated at first sight to awaken a feeling of revulsion in the 
beholder. Like the wasp, the salamander, and other animals whose conspicuous tints indicate 
their poisonous or other baneful properties, the heloderm is distinguished by a lurid ground- 
colour, varying in individuals from yellow-orange to flesh-pink, upon which are superimposed 
bold, network-like markings of blue-black or dark brown tints. Along the tail these reticu- 
lations usually take the form of more or less 
irregular rings. 
Although the heloderms possess such 
deadly properties, those at the Zoo manifest 
a by no means aggressive disposition, and 
allow their keeper or even strangers to handle 
them with impunit}'. In experiments pur- 
posely made to substantiate or refute the 
previously current rumours as to the poison- 
ous nature of these animals, two guinea-pigs 
succumbed to bites received in the course 
of the day. The owner of the reptiles, who 
was also bitten on one occasion through 
incautiously handling, suffered very severe, 
though happily not fatal, effects. In con- 
nection with its poison-dealing properties it 
is found that it possesses certain long and 
fang-like teeth, wdiich are set loosely in the 
j jaw^s, and which have grooves before and 
Phsu by IV. saviUe-Kent, F.z.s. beliiiid foi' the traiismissioii of the poison, 
SPINOUS LIZARD, OR MOUNTAIN-DEVIL which is secreted by special glands situated 
This species feeds exclusively upon ants cloSC tO thcil" baSC. The faVOUl'lte habitat of 
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