“The ‘pieuvre’ has _no muscular organisation_, no menacing cry, no breast-plate, no horn, no dart, no tail with which to hold or bruise, no cutting fins, or wings with claws, no prickles, no sword, no electric discharge, no venom, no talons, _no beak_, no teeth.... It has no bones, _no blood_, _no flesh_. It is soft and flabby. _It is an empty flask; a skin with nothing inside it. Its eight tentacles may be turned inside out, like the fingers of a glove. It has a single orifice, which is both vent and mouth. The same opening performs both functions._” [Illustration: Fig. 3. Mandibles of Octopus. (_O. vulgaris_).] So says the novelist. The naturalist knows that it has a complete and perfect muscular organisation; muscles which serve to retract and depress the funnel, bundles of strong muscles passing along the arms and branching to each of the suckers, within which other _fasciculi_ of muscular fibres converge from the circumference to the centre, and by their contraction produce the vacuum which gives to the animal its power of adhesion,—muscles all over its body, and a mass of muscles of such strength to work the powerful beak, that if anyone, believing the fictionist, were to place his finger in the small circular orifice in the centre of the base of the arms, he would possibly learn practically that it is not “an empty flask with nothing in it.” A sharp nip might perhaps teach him that it has not only muscles, but a mouth and head also. For just within the oral cavity lie, retracted and hidden, but ready for use when wanted, a pair of horny mandibles which bite vertically, like the beak of a parrot or turtle, except that the lower mandible is the longest and overlaps the upper, and are so hard that they can not only tear the softer animals the octopus is able to catch, but also break up the shells of lobsters, crabs, and mussels, which are its usual food. The head contains a brain, from which arises the system of nerves; and the animal has a sense of smell, and organs of hearing and taste, besides those which are apparent on its exterior, namely, of sight and touch. Instead of having “no blood,” it is furnished with a complete circulatory apparatus consisting of one systemic and two branchial hearts, arteries which distribute the blood through all parts of the body, and a system of veins or canals by which it returns towards the gills, of which breathing organs the animal has two—one on each side. By the alternate expansion and contraction of the bladder-like mantle-sac—an action resembling that of a pair of bellows—the water is pumped into contact with these gills, which convey to the blood the oxygen contained in it; and when its life-giving, purifying gas has been extracted from it, it is expelled by the muscular, valved funnel, or syphon tube, which has also another function, to be presently described. Far from being “a skin with nothing inside it,” from the beak and mouth (within which is a