The discussion of the curious lizard found in our Western Territories and in Mexico, and variously known as the “Montana alligator,” “the Gila monster,” and “the Mexican heloderma,” is becoming decidedly interesting.

As noted in a recent issue of the SCIENTIFIC AMERICAN, a live specimen was sent last summer to Sir John Lubbock, and by him presented to the London Zoological Gardens.  At first it was handled as any other lizard would be, without special fear of its bite, although its mouth is well armed with teeth.  Subsequent investigation has convinced its keepers that the creature is not a fit subject for careless handling; that its native reputation is justified by fact; and that it is an exception to all known lizards, in that its teeth are poison fangs comparable with those of venomous serpents.

Speaking of the Mexican reputation of the lizard, in a recent issue of Knowledge, Dr. Andrew Wilson, whose opinion will be respected by all naturalists, says that “without direct evidence of such a statement no man of science, basing his knowledge of lizard nature on the exact knowledge to hand, would have hesitated in rejecting the story as, at least, improbable.  Yet it is clear that the stories of the New World may have had an actual basis of fact; for the Heloderma horridum has been, beyond doubt, proved to be poisonous in as high a degree as a cobra or a rattlesnake.

“At first the lizard was freely handled by those in charge at Regent’s Park, and being a lizard, was regarded as harmless.  It was certainly dull and inactive, a result probably due to its long voyage and to the want of food.  Thanks, however, to the examination of Dr. Gunther, of the British Museum, and to actual experiment, we now know that Heloderma will require in future to be classed among the deadly enemies of other animals.  Examining its mouth, Dr. Gunther found that its teeth formed a literal series of poison fangs.  Each tooth, apparently, possesses a poison gland; and lizards, it may be added, are plentifully supplied with these organs as a rule.  Experimenting upon the virulence of the poison, Heloderma was made to bite a frog and a guinea pig.  The frog died in one minute, and the guinea-pig in three.  The virus required to produce these effects must be of singularly acute and powerful nature.  It is to be hoped that no case of human misadventure at the teeth of Heloderma may happen.  There can be no question, judging from the analogy of serpent-bite, that the poison of the lizard would affect man.”

[Illustration:  HELODERMA HORRIDUM, OR GILA MONSTER]

In an article in the London Field, Mr. W.B.  Tegetmeier states that this remarkable lizard was first described in the Isis, in 1829, by the German naturalist Wiegmann, who gave it the name it bears, and noted the ophidian character of its teeth.

In the Comptes Rendus of 1875, M.F.  Sumichrast gave a much more detailed account of the habits and mode of life of this animal, and forwarded specimens in alcohol to Paris, where they were dissected and carefully described.  The results of these investigations have been published in the third part of the “Mission Scientifique an Mexique,” which, being devoted to reptiles, has been edited by Messrs. Aug.  Dumeril and Becourt.