is well suited to their habits and mode of life. Animals purely swimmers, and which hunt and overtake their prey by speed, would be impeded by having to drag after them a bundle of lengthy appendages trailing heavily astern. But a long reach of arm is an advantage, instead of a hindrance, to the octopus; for, although it can swim on occasion, its ordinary habit is, either to rest suspended to the side of a rock, to which it clings with the suckers of several of its arms, in the position shewn in the frontispiece, or to remain lurking in some favourite cranny; its body thrust for protection and concealment well back in the interior of the recess; its bright eyes keenly on the watch; three or four of its limbs firmly attached to the walls of its hiding-place—the others gently waving, gliding, and feeling about in the water, as if to maintain its vigilance, and keep itself always on the alert, and in readiness to pounce on any unfortunate wayfarer that may pass near its den. To small fish, crustacean or mollusc, the slightest contact with even one of those lithe arms is fatal. Instantaneously as pull of trigger brings down a bird, or touch of electric wire explodes a torpedo or a mining fuse, the pistons of the series of suckers are simultaneously drawn inward, the air is removed from the pneumatic holders, and a vacuum created in each; the victim strives to escape; a further retraction of the central part of the disc makes all secure; and, as arm after arm, containing a perfect mitrailleuse of inverted air-guns, takes horrid hold, battery after battery of them is brought to bear, and the pressure of the air is so great that nothing can effect the relaxation of their retentive power but the destruction of the air pump that works them, or the closing of the throttle-valve by which they are connected with it.[12]