THE SERPENT’S TONGUE 145 
there are vulnerable spots and weak joints in the 
defensive armour of all animals. What I wish to 
draw attention to is the fact that, speaking meta- 
phorically, the serpent, of all creatures that kill 
their own meat, is the most unsportsmanlike in its 
methods, that it has found out and subtly taken 
advantage of the most secret and unsuspected 
weaknesses of the animals on which it preys. 
We have seen how the common snake catches 
the frog; but frogs are found only in wet places, 
and snakes abound everywhere, and the sedentary 
snake of the dry uplands must feed on the nimble 
rodent, volatile bird, and elusive lizard. How does 
he manage to catch them? For considering how 
alert and quick-sighted these small hunted creatures 
are, it must, I think, be assumed that the snake 
cannot, except in rare instances, approach them 
unseen and take them unawares. I believe that 
in many cases the snake succeeds by approaching 
its intended victim while appearing to be stationary. 
This stratagem is not confined to the ophidians: 
in a somewhat different form it is found in a great 
variety of animals. Perhaps the most familiar 
example is afforded by the widely distributed 
hunting-spider. The plan followed by this spider, 
on a smooth surface where it cannot hide its form, 
is to advance boldly towards its prey, and when 
the fly, who has been suspiciously watching its 
approach, is about to dart away, to become motion- 
less. This appears to excite the fly’s curiosity, and 
he does not take flight; but very soon his restive 
