270 



HARDWICKE'S SCIENCE-GOSSIP. 



THE POISONOUS LIZARD OF MEXICO 

 {HELODERMA HORRIDUM). 



MR, W. TEGETMEIER recently gave the fol- 

 lowing account of this anomalous lizard in the 

 " Field." The Gennan naturalist Wiegmann described 

 in the " Isis," in the year 1829, a new lizard, under the 

 title of Helodcrma horridiim. This lizard differs from 

 Lacertine animals in general in the circumstance of 

 the teeth having a marked ophidian character. 



The heloderme, according to M. F. Sumichrast, 

 inhabits the hot zone of Mexico— that intervening 

 between the high mountains and the Pacific in the 

 districts bordering the Gulf of Tehuantepec. It is 

 found only where the climate is dry and hot ; and on 

 the moister eastern slopes of the mountain chain that 

 receive the damp winds from the Gulf of Mexico it is 

 entirely unknown. Of its habits but little is known, 

 as it appears to be, like many lizards, nocturnal, or 

 semi-nocturnal, in its movements ; and moreover it is 

 viewed with extreme dread by the natives, who 

 regard it as equally poisonous with the most venomous 

 serpents. It is obviously, however, a terrestrial 

 animal, as it has not a swimming tail flattened from 

 side to side, nor the climbing feet that so character- 

 istically mark arboreal lizards. Sumichrast further 

 states that the animal has a strong nauseous smell, 

 and that when irritated it secretes a large quantity of 

 gluey"saliva. In order to test its supposed poisonous 

 property, he caused a young one to bite a pullet under 

 the wing. In a few minutes the adjacent parts became 

 violet in colour, convulsions ensued, from which the 

 bird partially recovered, but it died at the expiration 

 of twelve hours. A large cat was also caused to be 

 bitten in the foot by the same heloderme ; it was not 

 killed, but the limb became swollen, and the cat 

 continued mewing for several hours, as if in extreme 

 pain. The dead specimens sent to Europe have been 

 carefully examined as to the character of the teeth. 

 Sections of these have been made, which demonstrate 

 the existence of a canal in each, totally distinct from 

 and anterior to the pulp cavity ; but the soft parts 

 have not been examined with sufficient care to deter- 

 mine the existence or non-existence of any poison 

 gland in immediate connection with these perforated 

 teeth. 



Such may be regarded as a summary of all that was 

 known respecting this animal until the i6th of July, 

 when a living specimen, some nineteen inches in 

 length, was presented by Sir John Lubbock to the 

 Zoological Gardens. It arrived in a long tin box 

 about four inches square by twenty inches long. The 

 door at one end covered a small opening, through 

 which Mr. Bartlett was unable to shake out the 

 creature ; so he seized it by the head and deposited 

 it in a cage, little suspecting the risk he was incurring 

 of a venomous bite. 



Yqx some days the heloderme refused every kind of 



food offered to it. A live frog placed in the cage 

 was bitten, and, after a few seconds, liberated, but it 

 died in convulsions almost immediately ; a guinea 

 pig, bitten in the hind leg, died convulsed in three 

 minutes ; and some young rats perished even more 

 quickly. As the animal had not been fed since its 

 despatch from Mexico, there seemed every proba- 

 bility of its dying of inanition, when it was tried with 

 a hen's egg, broken in a shallow dish ; this it lapped 

 up with its large, strap-shaped, fleshy tongue, which, 

 like that of most of its congeners, is bifurcate at the 

 tip. 



On my second visit to it on Thursday morning to 

 verify the correctness of the very characteristic en- 

 graving which accompanied my article, Mr. Bartlett 

 and his son very kindly proposed to feed it again. A 

 couple of eggs were procured, one being a very small 

 pullet's egg, weighing about an ounce. On inquiring 

 of the keeper, we found that he had already given it 

 a hen's egg in the morning ; but, nevertheless, the 

 pullet's egg was placed on the shingle at the bottom 

 of the cage, which is in the reptile house. On our 

 drawing back from the cage, the heloderme at once 

 made for the egg, passed his long fleshy tongue over 

 and around it, and then opened his mouth to seize it ; 

 the egg being rather large, it kept slipping away, 

 until it was pushed by the animal to the front of the 

 cage, where he succeeded in biting through the shell 

 and licking out the contents, concluding by plunging 

 the fore part of his head into the interior, so that no 

 portion could escape. 



From the readiness with which eggs are attacked, 

 it appears obvious that they constitute a large portion 

 if not the entire, of the animal's natural food. I pro- 

 pose trying it with those of pigeons, which will, in 

 consequence of their smaller size, be eaten with less 

 difficulty, and I shall try one or two at an advanced 

 period of incubation. But should the animal be ex- 

 clusively an egg eater, the question arises as to the 

 possession of the poisonous properties that it un- 

 doubtedly possesses, and the useful purpose they sub- 

 serve in the economy of the animal. 



The general colour is a creamy buff", with dark 

 brown markings disposed in a not unpleasing pattern. 

 The front part of the head and muzzle is entirely dark, 

 the upper eyelid being indicated by a light stripe. 

 The entire body is covered with circular warts. 



The animal is one of considerable interest to 

 naturalists, as the existence of a poisonous lizard had 

 been doubted by many observers. 



Otters in co. Down., — Otters are still to be 

 found on the river Lagan, at Maralin, in co. Down, 

 fourteen miles from Belfast, where two fine specimens 

 were shot this year. The Lagan at the place is only 

 a small stream, but has been given an unnatural 

 depth by some mill dams or weirs on it, and so it 

 provides suitable retreats for the otters. 



