THE LONG-ARMED AND GREEN POLYPE.

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THE LONG-ARMED AND GREEN POLYPE.

POLYPE.

These are two species which will fully illustrate the nature of the whole tribe. They are found in clear waters, and inay generally be seen in small ditches and trenches of fields, especially in the months of April and May. They affix themselves to the under parts of leaves, and to the stalks of such vegetables as happen to grow immersed in the same water; and they feed on the various species of small worms, and other aquatic animals that happen to approach. When any animal of this kind passes near a Polype, the Polype suddenly catches it with its arms, and dragging it to its mouth, swallows it by degrees, much in the same manner as a snake swallows a frog. Two Polypes, may occasionally be seen in the act of seizing the same worm at diff erent ends, and dragging it, in opposite directions, with great force. It sometimes happens, that, while one is swallowing its respective end, the other is also employed in the same manner; and thus they continue swallowing, each his part, until their mouths meet. They then rest for some time in this situation, till the worm breaks between them, and each goes off with his share. But when the mouths of both are thus joined together upon one common prey, a more dangerous combat now and then ensues. The largest Polype gapes and swallows his antagonist; but what is extremely wonderful, the animal thus swallowed seems to be a gainer by the misfortune. After it has lain in the conqueror's body for about an hour, it issues unhurt, and often in possession of the prey that had been the original cause of contention. The remains of the animal on which the Polype feeds are evacuated at the mouth, the only opening in the body. The Polype is capable of swallowing a worm thrice its own size: this, though it may at first appear incredible, is easily understood, when we consider that the body of the Polype is extremely extensile, and is dilated on such occasions to a surprising degree.

The species are multiplied, for the most part, by a kind of vegetation, one or two, or even more young-ones, emerging gradually from the sides of the parent animal; and these young-ones are frequently again prolific before they drop off: so that it is no uncommon thing to see two or three generations at once on the same Polype.

But the most astonishing particular respecting this animal is that, if a Polype be cut in pieces, it is not destroyed, but is multiplied by dissection; it is thus literally

Rich from its loss, and fruitful from its wound.

It may be cut in every direction that fancy can suggest, and even into very minute divisions, and not only the parent stock will remain uninjured, but every section will become an 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 natural functions.

M. Trembley, of Geneva, ascertained that different portions of one Polype could be engrafted on another. Two transverse sections brought into contact will quickly unite, and form one animal, though each section belong to a different species. The head of one species may be engrafted on the body of another. When one Polype is introduced by the tail into another's body, the two heads unite, and form one individual. Pursuing these strange operations, M. Trembly gave scope to his fancy, and, by repeatedly splitting the head and part of the body, he formed hydras more complicated than ever struck the imagination of the most romantic fabulists.

These creatures continue active during the greatest part of the year, and it is only when the cold is most intense that they feel the general torpor of nature. All their faculties are then, for two or three months, suspended. But if they abstain at one time, they make ample amends in their voracity at another; and, like all those animals which becomes torpid in winter, the meal of one day suffices them for several months.

ANIMALCULES.

THE animals of the Linnean order Infusoria are extremely simple in their form, and generally invisible without a magnifying power. They are chiefly found in infusions of animal and vegetable substances.

OF THE VORTICELLA TRIBE.

THE Vorticellæ, or Wheel Animals, are the most remarkable of all animalcules, not only in their structure, but also in their habits and production. In general form they bear great affinity to the polypes, having a contractile, naked body, furnished with rotatory organs round the mouth; and indeed many microscopical writers have denominated them Cluster-polypes. They are almost invisibly minute, and, during the summer months, are generally found in clear, stagnant waters, attached to the stalks of the lesser water-plants, where they feed on animalcules still smaller than themselves. Many of the species are found in groups, sometimes formed by the mere approximation of several individuals, and at other times by the ramified or aggregate manner in which they grow. Their various motions, like like those of the polypes, are generally exerted only for the purpose of obtaining prey. The rotatory motion of their tentacula causes an

THE COMMON WHEEL ANIMALCULE, ETC.

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eddy in the water, around each individual, sufficient to attract into its vortex such animalcules as happen to swim near; these the little creature seizes, by suddenly contracting its tentacula and enclosing them in the midst. In several of the species the stems, into which they occasionly withdraw themselves, are somewhat rigid or scaly. The young-ones are carried in oval integuments on the outside of the lower part of the stems; and, when ready to issue forth, the parents aid their extrusion, where such is necessary, by writhing their bodies, or striking the little vesicle. . As soon as the young-one is liberated from its prison, it fixes itself, and commences the necessary operations to procure its food.

THE COMMON WHEEL ANIMALCULE AND THE CONVALLARIAN

VORTICELLA.

If the water that is found standing in gutters of lead, or the sediment it has left behind, has any appearance of a red or dark brown color, it will almost always be found to contain these animalcules. And, in the summer-time, if a small quantity of this dust be put into water, and placed under the microscope, it seldom fails to yield them in considerable numbers. They are denominated Wheel Animals, from their being furnished with a pair of instruments on the anterior part of their body, which, in figure and motion, somewhat resemble wheels.

These animalcules may be kept for several months out of water, and in a state of perfect dryness, without losing the principle of life. When dry, they are of a globular form, and about the size of a grain of sand. If put into water, after the space of about half an hour a languid motion begins. The globule turns itself about, lengthens by degrees, and soon afterwards becomes very lively. In a short time it protrudes its wheel, and swims about in search of food; or fixing itself by the tail, brings the food to it by its rotatory organs, which throw the whole circumjacent fluid into a violent commotion. After its hunger is satisfied, it generally becomes quiescent; and sometimes resumes even its globular form.

During the time it is in action, it frequently changes its shape and appearance: this, and the sudden transformation of the head, are equally surprising and singular. From being very taper, the head sometimes becomes, almost instantaneously, as broad as any part of the body, and protrudes its curious machinery. The circular bodies projecting from the animal in this state, whirl round with considerable velocity. As they are very transparent, the edges excepted, which are set with numerous fibrillæ, it is difficult to distinguish how the rotatory motions are performed; or whether their figure be flat, concave, or conical. They are, however, projected from tubular cases, into which the animal can withdraw them at pleasure. They sometimes turn the same way, and sometimes different ways at the same time.

All the actions of this creature indicate great sagacity and quickness of sensation.

OF THE VIBRIO TRIBE.

In this numerous tribe, the animals (nearly invisible to the naked eye) are of a simple, round, and elongated form. Several of them are found in vegetable infusions, and some in stagnant water: a few have been discovered in putrid sea-water, one in vinegar, and two in paste and infusions of grain.

THE EELS IN PASTE, AND IN BLIGHTED WHEAT.

From the general round and elongated form of these animalculæ, all the microscopical writers have been led to distinguish them by the appellation of Eels, although even the most gigantic individuals are seldom the tenth of an inch in length.

In order to procure those which are found in paste, the following simple process is recommended: boil some flour in water, adding to it a few drops of vinegar; put this into a coarse cloth, and bury it in an earthen pot, which has a hole in the bottom, and which is partly filled with earth, the pot is then to be exposed to the heat of the sun in summer, or kept in a warm place in the winter, for ten or twelve days, at the end of which time, if examined with a glass, it will be seen to contain a great abundance of these animalcules, which move about in every direction, with wonderful strength and rapidity.

If, from a small quantity of the paste diluted with water, one of the Eels be separated, and removed into a drop of water ready prepared on a separate glass, and there be cut asunder with a lancet or very sharp penknife, the mode in which the young-ones come to life may at any time be observed. Several oval bodies will be seen to issue from the wound. These are the offspring, in different stages of maturity, each coiled up and enclosed in its proper membrane. The largest and most forward of the group break through this delicate integument, unfold themselves, and wriggle nimbly about in the water. Others escape from their confinement, uncoil themselves, and move more slowly; and those which are least mature, continue entirely without motion; more than a hundred have thus been observed to issue from a single individual. This circumstance will readily account for their very sudden and prodigous increase.

It is an extremely singular circumstance, that in the latter part of the year, and during winter, these Eels are oviparous, whilst at other seasons they produce living offspring.

The Eels of blighted Wheat are found in those ears, the grains of which appear blackish, as if scorched, and the inside of which contains a soft, white substance. If these grains be soaked in water for a few hours, a great number of the animalcule will be found, some of them sufficiently large to be visible without the aid of magnifying powers.

They are oviparous; and the eggs, when at full growth, are nearly of a cylindrical shape, with both the ends rounded. These issue from

THE PROTEAN VIBRIO GLOBULAR VOLVOX.

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two little protuberances at the posterior extremity of the body. In the microscope, two generations may often be seen at the same time in the same animal, some of them almost in a state of maturity, and others small.

In blighted grains of wheat, which have been kept dry even for years, these animalcula have been found after a soaking for ten or twelve hours in water.

THE PROTEAN VIBRIO.

This is a species which has derived its name from its very singular power of assuming different shapes, so as sometimes with difficulty to be distinguished for the same animal. When water, in which any vegetable has been infused, or in which any animal substance is preserved, has stood undisturbed for some days, a slimy substance will be found on the sides of the vessel, some of which, if viewed in a microscope, will be found to contain, among several other animalcules, the Proteus. It is pellucid and gelatinous; and generally swims about, with a long neck and bulbous body, and with great vivacity. Sometimes it stops for a minute or two, and stretches itself out, apparently in search of prey. When alarmed, it immediately draws in its neck, becomes more opake, and moves sluggishly. It will then perhaps, instead of its former long neck, push out a kind of wheel machinery, the motions of which draw a current of water, and, along with this, probably its prey. Withdrawing the wheel, it will, sometimes, for several seconds, remain nearly motionless, as if weary; then, protruding its long neck, it will resume its former agility; or, instead, adopt in succession a multitude of different appearances.

OF THE VOLVOX TRIBE.

NEARLY all the species of Volvox are invisible to the naked eye. They are simple, pellucid, and of spherical shape. One of the kinds is found in pure water, one in vegetable infusions, and others in water which has been kept in glass. The species hitherto ascertained, are only nine in number.

THE GLOBULAR VOLVOX.

During the spring and summer months, these animalculæ are every where to be found in stagnant water; and in winter, they may be produced in water by an infusion of hempseed or hay. Sometimes they are sufficiently large to be visible by the naked eye. They move round, rolling over and over like a bowl, spinning like a top, or gliding along smoothly without turning at all. Sometimes their motions are very slow, and at other times quick and active. Occasionally they may be seen to turn rapidly round, as if upon an axis, without moving out of their places.

Under the microscope, their bodies seem to be covered with numer