M. F. Sumichrast on the Habits of some Mexican Reptiles. 499 
Tam led to this supposition (in which, moreover, I am supported 
by what I have heard from the natives) by the fact that, during 
the dry season, from November to June, this reptile is very rarely 
met with, and it is only seen pretty frequently during the rainy 
season. 
The body of the Heloderma usually exhales a strong and nau- 
seous odour, the intensity of which increases at the period when 
the two sexes seek each other for the purpose of copulation. 
When the animal is irritated, there escapes from its throat a 
whitish glutinous fluid, secreted by very large salivary glands. 
If it be struck during this angry movement, it finally throws it- 
self upon its back, which has led the Indians to say, as a precept 
to be followed under such circumstances, that the scorpion must 
always be attacked in front, because it stings behind. This singular 
manceuvre, which the Heloderma repeats whenever it is menaced, 
is accompanied by deep breathings and by an abundant secretion 
of the glutinous saliva already mentioned. 
The natives consider the bite of the Heloderma to be exceed- 
ingly dangerous, and dread it as much as that of the most 
venomous serpents, such as the Tepoxo (Bothrops atrox) or the 
Mazacoatl (Atropos mexicanus*). In support of this pretended 
malignity, I have been told of a great number of cases in which 
ill effects were produced by the bite of the animal, or by eating 
its flesh in mistake for that of the Iguana. I wished to make 
some conclusive experiments on this point; but, unfortunately, 
all the specimens of the Heloderma which I could procure during 
my stay in the countries inhabited by it were so much injured 
that it was impossible to do so. Without giving the least credit 
to the statements of the natives, I am not absolutely disinclined 
to believe that the viscous saliva which flows from the mouth of 
the animal in moments of excitement may be endowed with such 
acridity that, when mtroduced into the system, it might occasion 
‘mconveniences, the gravity of which, no doubt, has been exag- 
gerated. 
The thickness of the integuments which protect the body of 
the Heloderma, and the hardness of the scaly tubercles with 
which they are covered, render it almost insensible to the hardest 
blows; and its instant death is caused only by deep wounds pro- 
duced by a cutting instrument or a gun-shot. The muscular 
* The Tepoxo, or Tepocho, is tolerably common in most of the subalpine 
regions of Mexico; the species is subject to a great number of variations. 
The name Mazacoatl signifies Stag-snake (from Mazalt, stag, and Coat, 
serpent): it has been given to this species on account of the scales turned 
up in the form of small horns, which fringe the upper margin of the eye- 
lids. This Ophidian, which is less common than the preceding one, in- 
habits the warm and temperate as well as the colder regions. 
