LIZARDS 



173 



AUSTRALIAN YORK OR MOUNTAIN -DEVIL 



A spinous lizard 'which inhabits the arid plains of Central Australia 



emerald-greenand 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 Girdle- 

 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 

 f 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 impunity. 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, which are set loosely in the 

 , jaws, and which have grooves before and 



Fht, h W. swiii,. KM, F.Z.S. behind for the transmission of the poison, 



SPINOUS LIZARD, OR MOUNTAIN-DEVIL which is secreted by special glands situated 



Thh species feeds exclusively upon ants close to their base. The favourite habitat of 



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