Then, again, the order of the Cephalopods, to which belong the cuttle-fish and the octopus (sacred to Victor Hugo), may be, for all we can say to the contrary, an order with a future.  Their kindred, the Gastropods, have, in the case of the snail and slug, learnt the trick of air-breathing.  And not improbably there are even now genera of this order that have escaped the naturalist, or even well-known genera whose possibilities in growth and dietary are still unknown.  Suppose some day a specimen of a new species is caught off the coast of Kent.  It excites remark at a Royal Society soiree, engenders a Science Note or so, “A Huge Octopus!” and in the next year or so three or four other specimens come to hand, and the thing becomes familiar.  “Probably a new and larger variety of Octopus so-and-so, hitherto supposed to be tropical,” says Professor Gargoyle, and thinks he has disposed of it.  Then conceive some mysterious boating accidents and deaths while bathing.  A large animal of this kind coming into a region of frequent wrecks might so easily acquire a preferential taste for human nutriment, just as the Colorado beetle acquired a new taste for the common potato and gave up its old food-plants some years ago.  Then perhaps a school or pack or flock of Octopus gigas would be found busy picking the sailors off a stranded ship, and then in the course of a few score years it might begin to stroll up the beaches and batten on excursionists.  Soon it would be a common feature of the watering-places—­possibly at last commoner than excursionists.  Suppose such a creature were to appear—­and it is, we repeat, a possibility, if perhaps a remote one—­how could it be fought against?  Something might be done by torpedoes; but, so far as our past knowledge goes, man has no means of seriously diminishing the numbers of any animal of the most rudimentary intelligence that made its fastness in the sea.

Even on land it is possible to find creatures that with a little modification might become excessively dangerous to the human ascendency.  Most people have read of the migratory ants of Central Africa, against which no man can stand.  On the march they simply clear out whole villages, drive men and animals before them in headlong rout, and kill and eat every living creature they can capture.  One wonders why they have not already spread the area of their devastations.  But at present no doubt they have their natural checks, of ant-eating birds, or what not.  In the near future it may be that the European immigrant, as he sets the balance of life swinging in his vigorous manner, may kill off these ant-eating animals, or otherwise unwittingly remove the checks that now keep these terrible little pests within limits.  And once they begin to spread in real earnest, it is hard to see how their advance could be stopped.  A world devoured by ants seems incredible now, simply because it is not within our experience; but a naturalist would have a dull imagination who could not see in the numerous species of ants, and in their already high intelligence, far more possibility of strange developments than we have in the solitary human animal.  And no doubt the idea of the small and feeble organism of man, triumphant and omnipresent, would have seemed equally incredible to an intelligent mammoth or a palaeolithic cave bear.