The favorite food of cerebratulus lactus is said to be another abundant burrowing worm, the nereid, which is nearly as large in diameter, belongs to a higher order, and has powerful biting jaws. The victim always is swallowed tail first. Its burrow is a U-shaped tube in which it is unable to turn around. The nemertean probes through the mud for the tail end in such a burrow. The nereid, seized from behind, cannot bring its fighting apparatus into use. Actually, however, it never appears to struggle against being swallowed—a remarkable fact since nereids fight fiercely among themselves. The reason, it has been postulated, is that the victim’s nervous system is paralyzed by the poisonous slime excreted by cerebratulus. When a minute drop of this is placed on the tongue, it parches the whole mouth and the intensely bitter taste remains a long time. The worm requires about ten minutes to swallow a nereid, but by that time the prey is half-digested. The flow of this mucous is quite copious. When several healthy worms are placed in a pail, the bottom is soon filled with a hardening mass of it from which the animals must be cut or pulled. When crawling, the worm exudes a mucous trail, like a snail. A comparable Mediterranean species, Nemertes borlasi, was described by the French naturalist Quatrefages: “This gigantic worm is from thirty to forty feet long, brown or violet, and shining as varnished leather. It lurks under stones and in hollows of rocks where it may be met with, rolled into a ball and coiled in a thousand seemingly inextricable knots which it is incessantly loosening and tightening by contraction of its muscles. The animal is nourished by sucking a kind of small oyster which attaches itself to various substances under water. When it has exhausted the food around, it extends its long, dark-colored, riband-like body, which is terminated by a head bearing some likeness to the head of a serpent. It pauses gently, moves from side to side as if endeavoring to investigate the ground, and finally succeeds in finding a stone to suit its purposes about fifteen to twenty feet from its former retreat. It then begins to unwind its coil and arrange itself in a new domicile. In proportion as one knot is loosened, another forms at the opposite extremity.” A report of the Gatty Marine Laboratory of St. Andrews University in Scotland tells of the species Cerebratulus angulatus, which was mistaken for a fish. “But when the fisherman stretched out his hand net to capture it, instantly to his astonishment it shot out to more than a yard long. In the laboratory it swam with undulatory up-and-down movements, as an eel swims laterally.”