writers, though not of Linnæus. This species is of large size, and as active in mischief as the true navalis. Mr. Thompson gives an interesting account of the rapidity with which it has destroyed wood-work in the harbour of Port Patrick; and, according to Mrs. Griffiths, the same species caused the destruction of the bridge at Teignmouth. It has been observed on various other parts of our coast, engaged in its constant task,-reducing beams of timber to dust, and undoing with persevering industry what the "lord of the creation" is at most pains to do.

In this task of undoing, the Teredo does not work alone. The wood-work that escapes his auger may fall to powder under the teeth of two minute Crustaceous animals (Limnoria terebrans and Chelura terebrans), not

so big as a grain of rice, but as active as "the mother of mischief" herself, and as untiring. These little creatures, which resemble minute wood-lice, or shrimps, attack, like

the Teredo, any submerged wood-work, and rapidly perforate it in all directions, till it is reduced to a mere shell, ready to fall to pieces on the slightest touch. The Limnoria, which is the larger of the two, bores directly into the timber, piercing deeply nearly at right angles with the surface; while the Chelura excavates obliquely, rather ploughing up the surface than forming a deep burrow. Its work of destruction proceeds with fearful rapidity, particularly where it follows, as is often the case, its friend, the Limnoria. The loosened surface is rapidly washed away by the action of the water, and a new one exposed, to be in turn ploughed over by the busy creature. Though the means in action seem small, if we regard merely the size of these destructive insects, yet, when countless multitudes establish themselves in a beam, the untiring play of their jaws soon reduces the most solid timber to powder. Nor is it only constantly submerged timber which suffers from them. They can endure to be left dry at low-water, and the Limnoria has been kept alive for a considerable time in its burrow by merely an occasional moistening of salt and water.*

Among the objects which occasionally float ashore, or drift about with the waves, are dark-coloured, roundish, or spindle-shaped bodies, of the size and colour of grapes, and hanging together in clusters. They are soft to the

* Kirby and Spence, vol. i. p. 204 in note (6th edit.) An excellent account of the Limnoria has been published by Dr. Coldstream, in Brewster's Journal; and Professor Allman has given us a most elaborate paper on Chelura, in which the structure of the animal is very fully detailed, in the Annals of Natural History, vol. xix. p. 361,

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MARINE GRAPES.

touch, with a tough skin, resembling Indian-rubber; one end is produced into a sort of point or nipple, and

young cuttle-fish enters on his career. Cuttle-fishes are, perhaps, the most singular in structure of all the marine animals we commonly meet with, and are interesting to the naturalist in a variety of ways. If it were only for the position which they occupy in our systematic arrangements, at the head of the great group of the Mollusca, and in close proximity to the Vertebrates, their history would be important, from its exhibiting points of union

between these subdivisions of the animal kingdom. In fact, while all their salient characters are those of molluscous animals, and some of them are furnished with shells formed like those of other Mollusca, there are evident traces of an internal skeleton, which, in the manner in which it is evolved and nourished, is exactly analogous to the skeleton of a Vertebrate, in what may be supposed its most rudimentary form. The prin

cipal mass of nervous matter, or, as we may call it, the brain, is lodged in an obvious skull; the eyes are of a type of structure much more perfect than in any other Mollusc, and approaching closely to the complex structure of this organ in Vertebrates; it has a set of olfactory nerves, and a well-formed ear; and the nerve of taste is well developed, if we may judge by the vascular character and mobility of the tongue. In all that constitutes the life of the animal,-in his internal organs, his senses, and his intelligence, the cuttlefish, therefore, approaches very closely to a Vertebrate. Yet this creature has a body unlike anything we are accustomed to meet with among the higher animals, and whose similitude we must seek at the very base of the animal kingdom, among the polypes themselves. In those lowly-organized creatures we found a baglike body, with a mouth at one end, surrounded by a number of long arms, or tentacles, spreading round it in the form of a star. Here we again meet with the same type, or general idea, but in a state of advancement perhaps the greatest that such a type of organization admits of: instead of being minute gelatinous creatures, such as the Hydra of our ponds, some of the

animals of which we now speak, if travellers' stories may be trusted, more nearly resemble in their size, terrific aspect, and destructive powers, the Hydra of fabulous history. On our own shores there are many species, not, however, of a formidable size; but in tropical countries, species are said to occur with arms "nine fathoms long," which do not scruple to attack man himself, and to do so not merely when he is found naked in the water, but often when passing in a boat, which they sink with ease, by throwing their arms across it. Once the cuttle-fish fixes his hold, no effort that a fish is capable of making can throw him off; and the peculiar arrangement of the limbs, added to their admirable structure, place the unfortunate prey at the mercy of a singularly hard and sharp pair of jaws. When the cuttle-fish is at rest, he stands (like an Echinus) on his head, with his mouth in contact with the surface of what he stands upon; and round the mouth extends a circle of eight or ten arms, the whole of whose lower surface is studded with circular discs, of most elaborate structure, like so many cupping-glasses, or rather miniature air-pumps. When the cuttle-fish wishes to fix himself to any surface, he merely brings these discs in contact with it, and then, exercising voluntary muscles, he creates a vacuum under each

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"A friend of mine, long resident among the Indian isles, and a diligent observer of nature, informed me that the natives affirm, that some have been seen two fathoms broad over their centre, and each arm nine fathoms long. When the Indians navigate their little boats, they go in dread of them; and least these animals should fling their arms over, and sink them, they never sail without an axe to cut them off.”—Pennant, Brit. Zool. vol. iv. p. 45.