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 and sometimes different ways at the same

same way,

time.

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

Dr. Shaw, in his Naturalist's Miscellany, informs us, that the Convallarian Vorticella is frequently found on the stalks of the lemna or duckweed, as well as on those of other aquatic plants, and that it is one of the most elegant of the whole tribe. This animalcule is remarkable for the very sudden and starting manner in which it performs its motions; contracting its stem rapidly, and in a kind of convulsive manner, into a spiral form, and again gradually extending it to its former length.

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

DESCRIPTION. These animalculæ are filiform, with a dark shield on the back, surrounded with a white ring. The head is obtuse.

SYNONYMS. Colle. Cuvier.

Vibrio glutinis. Linn.-L'Anguille de la

* DESCRIPTION. The animals of this species taper towards each end, and are pellucid.

SYNONYMS. Vibrio anguillula. Linn.-Vibrion anguille.

Bosc.

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 prodigious 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 animalculæ 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 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 animalculæ have been found after a soaking of 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

DESCRIPTION. In this minute animalcule, one of the extremities terminates in a sharp point.

SYNONYMS. Vibrio Proteus. Linn.-Protée Tenace (Proteus tenax.) Bosc.

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 mov-` ing out of their places.

Under the microscope, their bodies seem to be covered with numerous globulets of different sizes. These

DESCRIPTION. This species is spherical, membranaceous, and has upon its body various-sized globulets or homogeneous molecules. It is of a greenish or yellowish colour.

SYNONYMS. Volvox Globator. Linn.-Volvox globuleux. Bosc.-Le Volvoce sphérique. Cuvier.

appear to contain the young-ones, for, when they are in a proper state of maturity, the exterior membrane bursts open, and the young-ones pass through the fissure: shortly after this the parent animalculæ die and melt away.

The globulets, while in the body of the parent, contain other globulets, and these again others; so that it may, with propriety, be said, that these animalculæ bear children, grand-children, and great grand-children all at the same time.

THE BUBBLE VOLVOX *.

I shall conclude this work, with La Martiniere's description of Volvox Bulla, a species of animals nearly the most simple of any that have yet come to our knowledge. "They consist (he says) only of oval bodies, similar in shape to soap-bubbles, arranged in parties of three, five, six, and nine: among them are also some solitary ones. These collections of globules, being put into a glass filled with sea-water, described a rapid circle round the glass by a common movement, to which each individual contributed by the simple compression of the sides of its body, probably the effect of the reaction of the air with which they were filled. It is not, however, easy to conceive how these distinct animals (for they may be readily separated without deranging their economy) are capable of concurring in a common motion. These considerations, together with the form of the animal, recalled to my mind, with much satisfaction, the ingenious system of M. de Buffon; and I endeavoured to persuade myself, that I was about to witness one of the most wonderful phenomena of nature, supposing that these molecules, which were now employed in increasing or diminishing their number, or performing their revolutions in the glass, would soon assume the

DESCRIPTION. This animalcule is scarcely visible to the naked eye. It is of a somewhat oval shape, and membrana

ceous.

SYNONYM. Volvox Bulla. Linnæus.