142 LIFE AND HER CHILDREN. 
of a far higher structure, who have managed to gain 
a much better position in the world. In each of our 
groups of animal life we have found some special 
advantage which has enabled them to spread their 
children over the world ; the sponges had their 
co-operative life and their protecting skeletons, the 
lasso-throwers their poisonous weapons, the prickly- 
skinned animals their tube feet and stony casing, the 
mollusca their wonder-working mantle, but among 
them all we have not yet met with that power of 
moving quickly, without which no creature is ever 
very intelligent. It is true that the octopus can 
shoot rapidly through the water, and is at the same 
time the most intelligent animal we have yet learned 
to know ; but its quick movements are all in the 
water ; when it scrambles along the shore it is slow 
and awkward, while the other crawlers, the sluggish 
snail or the creeping star-fish, are not any more rapid. 
And yet it is clear that the power of getting quickly 
over the ground must be an advantage in the struggle 
for life, and we shall see that it is this power and 
the intelligence accompanying it which has raised 
the most advanced animals in the sixth division to 
such a high position as that of the bee and the ant. 
Nothing, however, is learnt in a moment, and 
therefore you must not be surprised that the worm 
and the leech, which you would probably consider 
rather slow animals, are the first examples of the 
more active creatures. Nevertheless, if you could 
start either of these animals on a fair race with a 
snail, though they might not appear to hurry yet 
you would find they would beat him hollow. The 
accompanying picture is one given by Sir Emerson 
