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to see two or three generations at once in the same polype. But the most curious particular respecting this animal is, its multiplication by dissection. It may be cut in every direction, and even into very minute divisions, and not only the parent stock will remain uninjured, but every section will become a perfect animal. Even when turned inside out, it suffers no material injury; for in this state it will soon begin to take food, and to perform all its other animal functions.
Coupés vingt fois, vingt fuis ils vont se ranimer,
Sous les ciseaux féconds prompte à fructifier,
The hard or horny zoophytes are known by the name of corals, and are equally of an animal nature with the polype; the whole coral continuing to grow as an animal, and to form by secretion the strong or stony part of the coral, which at once may be considered as its bone and its habitation, and which it has no power of leaving *. Some of the coral tribe have their animal part approaching more to that of a medusa, than of a polype. Of this kind are those numerous corals known by the name of madrepores. The smaller corals are termed corallines, or sea-mosses; and are actually so many ramified seapolypes, covered with a horny case, to defend them from the injuries which they would otherwise be liable to, in the boisterous elements in which they
* Our hills are in many places full of them, and some rocks are entirely of their formation. Many seas are becoming every year more difficult to navigate, being nearly choked up by the habitations of animals almost too small for human perception,
are destined to reside. The principal genera of the corallines are: 1. Sertularia. 2. Tubularia. 3. Flustra. Those of the corals are, 1. Gorgonia, Venus's fan. 2. Isis. 3. Madrepora. 4. Millepora. 5. Tubipora.
II. ANIMALCULA INFUSORIA, or animalcules found in different liquids. These minute beings are principally to be observed, by the aid of the microscope, in such fluids as have had any animal or vegetable substance infused in them. The antients were totally unacquainted with this class of beings. To them, the mite was made the ne plus ultra, or utmost bound of animal minuteness; but the moderns, assisted by that powerful instrument, the microscope, have discovered whole tribes of animals, compared with which even mites may be considered as a kind of ELEPHANTS!
The microscope has opened the eye of man upon a world of innumerable animalcules, which people the three inhabitable elements of Nature. Myriads of them dance with the motes in the sunbeams, they swim by millions in a dew-drop, brew and prepare the glebe for vegetation, and ebb and flow with the air of our breath.
The principal genera of the Animalcula Infusoria are, 1. Vorticella. The v. convallaria is a beautiful transparent animalcule, formed like a bell-shaped flower, and furnished with a long tail or stem, by which it generally affixes itself to the stems and under-surface of the common lemna minor, or duckweed. The v. racemosa is still more elegant. It is found in clear stagnant waters during the summer months, attached to the stalks of the smaller water
plants. If submitted to the examination of the mieroscope, several small ramifications will be perceived to issue from a single stem, each terminated by an apparent flower, like that of a convolvulus. The whole is in the highest degree transparent, and the alternate expansion and contraction of the seeming flowers forms a very curious and interesting spectacle. The v. rotatoria, or wheel-animal, so named from the apparent rapid motion of the head, is remarkable for its strange power of restoration to life and motion, after being dried many months in a glass. 5. Cercaria. The c. mutabilis, or changeable cercaria, is the cause of that fine deep-green scum which appears on the surface of stagnant waters during the summer months.
Where the pool
Stands mantled o'er with green, invisible,
With various forms abounds. Nor is the stream
Though one transparent vacancy it seems,
3. Trichoda. The t. sol is a globe or ball, beset on all sides with very long diverging rays, having the appearance of a sun. It is about the size of a small pin's head, and is generally affixed to the stem of some small water-plant. This animalcule may be pulled or torn in pieces, by means of a pair of needles, or other convenient instruments, and, in the space of a single hour, each piece will be apparently complete, and perfectly globular like the original.-4. Volvox. The v. globator often equals the size of a pin's head. In the advanced state of spring, and again in autumn, it appears in immense numbers in the clearer kinds of stagnant waters. Its motions are irregular, in all directions, and, at the same time, rolling or spinning as if on an axis.-5. The vibrio is the largest of all the animalcular tribe.
One species of the v. anguillula, or eel-vibrio, inhabits acid paste; when full-grown, it measures the tenth of an inch in length. It is viviparous, and frequently produces a tribe of young*. Its general appearance, when magnified, is that of an eel t. The other species may be sometimes found in vinegar. -6, 7. Cyclidium and Monas are exceedingly small; a species, called the m. termo, when surveyed by the utmost powers of the microscope, still appears but as a kind of moving point, having merely a sensible diameter.
A countless swarm of animalcules will always appear in any vegetable infusion, after the space of a few days; as in the infusion of hay, beans, wheat, and other substances. The blueish appearance on the surface of plums, grapes, and many other fruits, is not a living world, but a mere vegetable efflorescence, which regularly takes place on such kind
III. The MOLLUSCA derive their name from the soft, fleshy nature of their body. This class includes those pulpy animals, which may either be destitute of an external covering, when they are called mollusca nuda, as the slug; or may be inclosed in one or more shells, as the snail, oyster, &c., when they are termed testacea.
1. Mollusca nuda are those soft-bodied animals, which are destitute of any truly shelly or very hard integument; though some particular genera have a
* If one of them be cut through the middle, several young ones coiled up and inclosed, each in a membrane, will be seen to proceed from the wound. More than one hundred young have issued from a single parent.
+ Mr. Baker, the celebrated microscopic observer, with an instrument of highly magnifying powers, saw these eels an inch and a half in diameter, and of a proportionate length. They swam up and down very briskly. The motion of their intestines was very visible: when the water dried up, they died in appa rent agonies, and their mouths opened very wide.
coriaceous or leathery covering. Most of them are furnished with tentacula, or feelers. The principal genera are:-1. Limax, slug. 2. Aplysia, a marine worm. 3. Doris, a sea-snail. 4. Nereis. 5. Terebella. 6. Pyrosoma. 7. Nais. 8. Sepia, cuttlefish. 9. Calamary, Loligo, pen-fish, or ink-fish. 10. Medusa, sea-blubber, sea-nettles. 11. Holothuria. 12. Actinia, sea-anemone. 13. Asterias, star-fish. 14. Echinus, sea-urchin.
The well-known Chinese preparation, called Indian-ink, is supposed to be no other than the black liquor found in the body of the cuttle-fish, carefully managed, perfumed, and formed into ornamental cakes. The eggs of this fish, of the size of small filberts, and of a black colour, are frequently seen on the sea-shore, and are popularly termed seagrapes. The dark inky fluid, which this animal emits when alarmed, not only tinges the water, so as to conceal its retreat, but is, at the same time, so bitter, as immediately to drive off its enemies.
Th' endangered cuttle thus evades his fears,
So tenacious are the sea-urchins of the vital principle, that, on opening one of them, it is no un-common circumstance to observe the several parts of the broken shell move off in different directions. The antients, according to Oppian, gave credence to a circumstance much more wonderful than this :
Sea-urchins, who their native armour boast,