[7] _Geographical Journal_, Nov., 1898. Yet neither strength nor speed, nor grasping arms, nor clinging suckers, nor tiger-like claws, nor parrot-like beak, can protect the cuttlefish against its supreme foe, the Sperm whale. But it has a method of defence, or rather of escape, often efficacious even here. When in danger, it is able to pour forth a copious stream of black liquid, which so thickens and darkens the water around, that the wily creature is hidden, and slips away beyond reach of its pursuer. The nervous system of the Cuttlefish is more developed than that of other Molluscs. Indeed, from the remarkable changes of colour seen when it is excited, and the tubercles which spring to view on its skin if it is made angry, one would be inclined to speak of its temperament as “highly irritable.” It also shows much more understanding than its cousins, the oysters and the clams. CHAPTER XXI. A GOODLY COMPANY OF CRABS “The slimy bottom of the Deep.”--_King Richard III._ In all the wealth of Ocean-life, perhaps no creature flourishes more abundantly than do Crabs and their relatives. We still talk of Jelly-fishes, Starfishes, Craw-fishes, Cuttlefishes, but no longer of Crab-fishes. Once upon a time that name was equally common. Everything that had its home in the sea was popularly supposed to be a fish. We know now that not one of the above belongs to any Fish tribe; yet in Conservative style we keep the old titles going. Crabs and Lobsters, Shrimps and Prawns, are members of the vast CRUSTACEAN division or family. They are so called on account of the hard protecting _crust_, or armour, by which their soft bodies are guarded. Chief and foremost among the numberless kinds included under this head is the busy vigorous sidling Crab. And very important animals are crabs, in the economy of the Ocean. Not only from their enormous numbers; not only from the wide extents of land and sea which own to their presence; not only from the fact that they form a principal item of food to fishes and even to whales; but also because at least one species is reckoned excellent eating for man. There are land-crabs as well as sea-crabs. There are deep-sea crabs, as well as shallow-water and shore crabs. [Illustration: A DEEP-SEA CRAB The holes in front are for the admission of water containing nutritious animal food _Face page 220_ ] There are crabs much less than half-an-inch across; and there are giant Japanese crabs, carrying heavy back-armour or “carapace,” about a foot in length and breadth, while the sprawling limbs extend to a yard and a half or more on either side. Those of ordinary sizes are found everywhere; in numbers beyond reckoning. Not only in tropic waters, but in moderate climes, and in frigid zones; alike near the poles and under the equator. Different species, of course, in different parts, but all connected.