Indeed, for my own part, I am strongly of opinion that there is sense existing in those bodies which have the nature[2729] of neither animals nor vegetables, but a third which partakes of them both:—sea-nettles and sponges, I mean. The sea-nettle[2730] wanders to and fro by night, and at night changes its locality. These creatures are by nature a sort of fleshy branch,[2731] and are nurtured upon flesh. They have the power of producing an itching, smarting pain,[2732] just like that caused by the nettle found on land. For the purpose of seeking its prey, it contracts and stiffens itself to the utmost possible extent, and then, as a small fish swims past, it will suddenly spread out its branches, and so seize and devour[2733] it. At another time it will assume the appearance of being quite withered away, and let itself be tossed[2734] to and fro by the waves like a piece of sea-weed, until it happens to touch a fish. The moment it does so, the fish goes to rub itself against a rock, to get rid of the itching; immediately upon which, the nettle pounces upon it. By night also it is on the look-out for scallops and sea-urchins. When it perceives a hand approaching it, it instantly changes its colour, and contracts itself; when touched it produces a burning sensation, and if ever so short a time is afforded, makes its escape. Its mouth is situate, it is said, at the root or lower part,[2735] and the excrements[2736] are discharged by a small canal situated above. CHAP. 69.—SPONGES; THE VARIOUS KINDS OF THEM, AND WHERE THEY ARE PRODUCED: PROOFS THAT THEY ARE GIFTED WITH LIFE BY NATURE. We find three[2737] kinds of sponges mentioned; the first are thick, very hard, and rough, and are called “tragi:”[2738] the second, are thick, and much softer, and are called “mani;”[2739] of the third, being fine and of a closer texture, tents for sores are made; this last is known as “Achillium.”[2740] All of these sponges grow on rocks, and feed upon[2741] shell- and other fish, and slime. It would appear that these creatures, too, have some intelligence; for as soon as ever they feel[2742] the hand about to tear them off, they contract themselves, and are separated with much greater difficulty: they do the same also when the waves buffet them to and fro. The small shells that are found in them, clearly show that they live upon food: about Torone[2743] it is even said that they will survive after they have been detached, and that they grow again from the roots which have been left adhering to the rock. They leave a colour similar to that of blood upon the rock from which they have been detached, and those more especially which are produced in the Syrtes of Africa.[2744]