Examples of Warning Colouration 
smelling froth ; but this bear readily devoured 
ordinary brown or green species. 
Among cold-blooded vertebrates the common 
European salamander, with its bright black and 
yellow markings, is a striking example of warning 
colouration ; its skin exudes, on pressure, a very 
poisonous secretion. 
Colonel A. Alcock has described a small 
siluroid sea-fish, brightly banded with black and 
yellow, and armed with poison spines. 
A well-known Indian poisonous snake, the 
banded Krait (Bungarus ceruleus), is conspicu- 
ously barred with wide bands of black and yellow ; 
and in South America there occur numerous 
species of coral snakes, in which red is added 
to these conspicuous colours. 
The only known poisonous lizard—the Helo- 
derm of Mexico—is conspicuously blotched with 
black and salmon-colour. 
Among birds, no instances of warning coloura- 
tion have been recorded, though Professor 
Poulton has suggested that possibly the striking 
and contrasted tints of many tropical species may 
be due to this cause. The suggestion is an in- 
genious one, but is at present totally unsupported 
by evidence. 
The skunks are often cited as an excellent 
example of warning colouration among mammals. 
Skunks are most conspicuously arrayed in black 
and white—the latter above, not below, as is 
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