VENOMS IN THE ANIMAL SERIES 323 
a way that showed that it was suffering acute pain. It was 
unable to stand, and remained stretched out on the same spot 
for a whole day, unable to get up, and completely stupefied. 
Interesting observations on the Heloderm have been made by 
J. Van Denburgh and O. B. Wight. The saliva of this lizard was 
found to be highly toxic at certain times, and harmless at others. 
When injected subcutaneously it produces various effects, such as 
miction, defecation, and abundant salivation, with accelerated 
respiration followed by vomiting. The animal drinks with avidity, 
and remains lying down, in a very depressed condition. Death 
finally supervenes, from arrest of respiration and also of the heart’s 
action. The poison likewise acts upon the arterial tension, which 
falls very rapidly and very markedly. The sensory nerves are also 
attacked; irritability is at first increased, then diminished, and at 
last entirely lost. These changes take place from behind forwards, 
and from the periphery to the centre. The coagulability of the 
blood is at first intensified and then lessened, as when acted upon 
by VIPERINE venom (H. Coupin).! 
C.—Mammals. 
The only mammal that can be considered to be provided with 
a poison-apparatus belongs to the Order Monotremata, and is known 
as the Duck-billed Platypus (Ornithorhynchus paradoxus or O. 
anatinus, fig. 125). The head of this animal is furnished with 
a kind of flat duck’s bi, armed with two horny teeth in the upper 
jaw, while the body, which is covered with dense fur, resembles that 
of a beaver. The tail is broad and flat; the legs are short, and the 
feet are provided with five toes, armed with strong claws and webbed. 
This singular animal is found only in Australia and Tasmania. 
It lives in burrows near watercourses, entered by holes which it, 
digs in the bank, one above, the other on the water-level. It spends 
1H. Coupin, La Nature, September 19, 1903. 
