ing "feet proceeding from the head." Of these the octopus, as its name indicates, has eight feet, or arms; for, though these long appendages are sometimes used as feet, they are habitually used as arms.
Of the octopoda family is the small paper nautilus or argonaut. How few of our readers who have admired this beautiful shell, with its mother-of-pearl lining, have realized that its former inhabitant was own cousin to the horrible devil-fish!—a female cousin, we must add, for the shell is not connected with the animal organically, but is held in position by two of the long arms, with the sole purpose of protecting the eggs. The male argonaut has no shell.
Though all the octopods, large or small, can swim freely at will, such is not their habit; they prefer to lie concealed, or partially so, on
Fig. 5.—Paper Nautilus (Argonauta argo).
the side or in the clefts of rocks. There the octopod's body is protected from the attacks of other animals, while it can extend its long feelers in search of prey, of which fish, mollusks, and crustaceans, are the principal objects. Its movements, when an object of food is perceived, are marvelously rapid, swifter than the flight of an arrow from the bow of an experienced hunter. The long, flexible arms grasp the victim; its hundreds of suckers, acting like pneumatic holders, make escape impossible; and, as the long arms draw the object nearer and nearer, the other shorter arms add their multiplied disks, forming "a perfect mitrailleuse of inverted air-guns, which take horrid hold, and the pressure of air is so great that nothing but closing the throttle-valve can produce relaxation." This throttle-valve is the neck, as we have before described. Those lengthy appendages, the limbs, are rather in the way when the animal is swimming, and would act as drag-anchors if left pendent; but the octopus usually draws them close alongside, whence they extend in an horizontal position, acting the part of a tail to a kite. It propels itself by drawing in and expelling water through its locomotory tube.
