The size, of course, varies. I have seen and _measured_ the arm five feet long, and as large at the base where it joins the central disc as my wrist; and were an octopus by any chance to wind its sucker-dotted cable-arms round a luckless bather, fatal would be the embrace, and horrible to imagine, being dragged down and drowned by this eight-armed monster; a worse death than being crushed by coiling serpents like ill-fated Laocoon.
I have often when on the rocks, in Esquimalt Harbour, watched my friend’s proceedings; the water being clear and still, it is just like peering into an aquarium of huge proportions, crowded with endless varieties of curious sea-monsters; although grotesque and ugly to look at, yet all alike displaying the wondrous works of Creative wisdom. In all the cosy little nooks and corners of the harbour the great seawrack (_Macrocystis_) grows wildly, having a straight round stem that comes up from the bottom, often with a stalk three hundred feet long; reaching the surface, it spreads out two long tapering leaves that float upon the water: this sea-forest is the favourite hunting-ground of octopi.
I do not think, in its native element, an octopus often catches prey on the ground or on the rocks, but waits for them just as the spider does, only the octopus converts itself into a web, and a fearful web too. Fastening one arm to a stout stalk, stiffening out the other seven, one would hardly know it from the wrack amongst which it is concealed. Patiently he bides his time, until presently a shoal of fish come gaily on, threading their way through the sea-trees, joyously happy, and little dreaming that this lurking monster, so artfully concealed, is close at hand. Two or three of them rub against the arms: fatal touch! As though a powerful electric shock had passed through the fish, and suddenly knocked it senseless, so does the arm of the octopus paralyse its victim; then, winding a great sucker-clad cable round the palsied fish—as an elephant winds its trunk round anything to be conveyed to the mouth—draws the dainty morsel to the centre of the disc, where the beaked mouth seizes, and soon sucks it in.
I am perfectly sure, from frequent observation, the octopus has the power of numbing its prey; and the sucking-discs along each ray are more for the purposes of climbing and holding-on whilst fishing, than for capturing and detaining slippery prisoners. The suckers are very large, and arranged in triple rows along the under-surface of the ray, decreasing in size towards the point, and possessing wonderful powers of adhesion.