The bristles, presumably, are almost entirely for defense; the spines for offense, and admirably fashioned for killing weaker animals. Both types of weapons can be retracted entirely inside the foot when not in use, but thrust out again immediately when needed. Aphrodite hermione, a close relative of the sea mouse, Dr. Johnston points out, “has in the dorsal branch of its feet bristles which may be described as lances. They are so small that a magnifying glass is needed to discover the workmanship, which excels in finish the finest instrument of man by the skill of the most expert artificer. A great number of these bristles garnish the extremity of each foot, and as they are stiff and serially arranged they form a hedge of spears around the body of the worm, placing it within a square of pointed pikes threatening at all points. Other bristles terminate in a knob within which is a barbed lance.” Still others are likened by Dr. Johnston to harpoons, produced from the body only as required. They are very sharply pointed bristles with the point attached to a shaft. The harpoon point, like the bayonet previously described, has a reverted tooth which cannot be withdrawn once it has been plunged into the body of the enemy. It can, however, be detached and left to fester in the wound. Some worms lose all their harpoons in their many fights. “There is scarcely a single weapon invented by the murderous genius of man,” commented the French naturalist Quatrefages concerning aphroditids on Bay of Biscay coasts, “whose counterpart and model could not be found among these worms. Here are the curved blades whose points present a double and prolonged cutting surface, sometimes on the concave edge as in the yataghan of the Arabs, sometimes on the convex border as in the oriental scimitar. We meet with weapons of offense and defense which remind us of the broad sword of our cuirassiers; the sabre-poignard of the artilleryman; the sabre-baionette of the chausseurs. We have harpoons, fishhooks, cutting blades in every form attached to the extremities of sharp handles. Destined to live by rapine and exposed to a hundred enemies, they need such weapons both for attacking and defense.” Some aphroditids swim with ease. The majority, however, are found between tide marks where they burrow in wet sand. A few occasionally trespass in tidal rivers. When placed in fresh water the animals soon die, in their death throes first ejecting a milky-white fluid which turns to blackish-green at the moment of death. Despite their heavy armament, the aphroditids are a favorite food of codfish. They are distributed generally all over the world. The monster of the race in the South Pacific sometimes reaches a length of five feet. _Eating Habits of Spiders_