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the superiority of things which are excellent. G. T. L.

ANIMALCULES.-No. II.

WE may now pass on to notice the digestive apparatus of these minute beings, as far as it is ascertained; but before entering into the subject, it must be premised that in many points great obscurity prevails, and that the observations of Ehrenberg are not always corroborated by those of other microscopic investigators. The term polygastrica, by which the present group of animalcules is distinguished, bears reference to the complexity of the digestive apparatus, which is stated to consist of a number of internal sacculi, or stomachs, in some, arising from the mouth itself by separate tubes, (see the

annexed figure,) in others, appended to a kind of intestinal canal, which traverses the body, and terminates either at the extremity of the body opposite to the mouth, as in Paramecium aurelia, (page 50,) or which, winding up, terminates in a depression near the mouth, as in Vorticella (page 51.) The sacculi, though distinguishable in the animals under ordinary circumstances, are rendered more conspicuous when the animals have swallowed water in which colouring matter is suspended, in a state of very minute division, but not chemically dissolved. Trembley, in his investigation of the structure of the hydra, adopted this method, and Gleicher attempted it, though unsuccessfully, in his investigations upon these animalcules. The fact is, that many of our metallic or earthy colouring materials immediately poison these creatures, when of course the experiment fails. This Ehrenberg tried in vain, with the indigo and gumlac of commerce, these substances being always contaminated with a slight admixture of white lead, which acts as an instantaneous poison; but with pure indigo,

or pure carmine, the experiments were successful.

When a minute portion of a very weak solution of indigo is added to a drop of water, containing vorticella, an animated scene ensues: eager for the food, which they swallow with avidity, they throw the cilia into rapid action, producing currents in the water, hurrying with them the particles of the indigo, in gyrations converging to the mouth. In a short time, a number of dark blue circular dots begin to show themselves on the transparent body of the animalcule, which are occasioned by the particles of the indigo accumulated in these situations; they also make manifest the intestinal tube, and their progress can be gradually traced through its extent. It was thus by a series of experiments, that Ehrenberg was at length enabled to determine the number of the sacs, or stomachs, and course of the intestinal tube. But it appears that all the sacs are not filled at the same time; many continue long without receiving any particles of colouring matter, and the whole course of the alimentary tube is not simultaneously tinted. The number of sacs thus distinguished, amounts to two hundred in some species; in others they are less numerous.

It is on the characters and positions of these sacs, and on the course of the presumed intestinal tube, that Ehrenberg has founded the divisions of this class; but Professor Jones, while he acknowledges that the views of this naturalist are sanctioned by general consent, is not disposed to admit their accuracy in all respects, and states that his own observations (made by means of a compound achromatic microscope, and employing powers nine-tenths, onehalf, one-fourth, and one-eighth of an inch focus) have led to very different conclusions. The positions of the orifices for the reception and rejection of aliment he found to be such as Ehrenberg has indicated; but the most patient investigation did not enable him to detect the arrangement of the tube, and the sacculi appended to it, figured and described by that author. He states that he has never been able to perceive, when one of the carnivorous animalcules has swallowed another that it has been conveyed, as was to be expected, into one of these, so called stomachs, but that he has traced it into "what seemed a cavity excavated in

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the general parenchyma of the body." In the next place, he states that these sacculi have no appearance of being attached to any tube by means of peduncles, or necks; and that in Paramecium aurelia (page 50,) so far from appearing to be connected with a central canal, as is represented by Ehrenberg, they are in continual circulation, moving up one side of the body and down the other, and even changing their relative positions, like the coloured granules visible in the gelatinous substance of the hydra. And, thirdly, he affirms that in no instance has he been able to detect a central tube at all, as depicted by Ehrenberg, much less the branches leading from it to the sacs; and he adds, that the circumstances attending the prehension of food, would, in themselves, lead us to imagine a structure different from that described by Ehrenberg. He adduces, by way of confirming his views, the changes of form which these animalcules undergo, when devouring prey nearly equal to themselves in bulk, and therefore incapable of entering into one of these sacs; the mouth dilates to engulph the victim, and when this is swallowed, the whole body, as in the hydra, becomes greatly distended. As an example in point, Professor Jones figures the flask animalcule (Enchelis pupa) in its ordinary state, preparing to attack its prey, in the act of engulphing it, partially swallowed, and wholly so. (See the engraving.) For other

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tinged with the juices of the prey on which the animal feeds; which juices, by some means unknown at present, they absorb, and thus charged, circulate through the gelatinous substance of the body. We may here, by way of note, observe, that some observations respecting the hydra, or fresh water polype, will be found in "Notes on the Month," for June, pages 204-207 in the Visitor for 1840.

With respect to the mouth of the polygastric animalcules, it is generally found to be a simple dilatable and contractile orifice; but in some species it appears under the form of a small projecting beak, or rather tube, composed of numerous teeth of an elongated shape, and calculated both for the prehension of food, and for bruising_it previously to its being swallowed. In these species, the mouth does not appear to be surrounded with cilia, which would be unnecessary, but which, when the mouth is a simple orifice, are required for the direction of the food to it.

There is no part of the history of these polygastric animalcules, more calculated to excite astonishment than that relative to their mode of reproduction, so different from that of other races of beings; and what is surprising, is, that the same individual, as it would appear, often reproduces in four different ways.

First, then, one mode of reproduction is by gemmules or buds, sprouting from the outer surface of the parent, as in the hydra. These little buds gradually assume their destined form, develope cilia, and become detached and independent, and in a short period afterwards attain to their full growth, giving origin to buds themselves.

Secondly. Another mode, which is seen in Volvox globator, is by minute globular bodies, of a dark green colour, covered like the parent with vibratile cilia, and which swim about in the interior of the body of the parent, where they appear to have ample space. The transparency of this animalcule, which is of a globular figure and of a delicate green, permits the germs it encloses to be readily seen. When they have attained a proper degree of developement, the outer skin of the parent bursts, and they emerge from their imprisonment, to undergo a like destiny.

Thirdly. The most usual mode, and it is the most extraordinary, by which

new animalcules are produced, is by the division of the animalcule itself into two or more portions, each portion becoming a perfect being, and again dividing in turn. In animalcules of an elongated form, the division generally takes place longitudinally, each side becoming a distinct being, with all its organs complete; but in oval animalcules, the division is transverse, first beginning with a median constriction which traverses till the separation is effected. Some animalcules increase both by gemmules, and by division, as the convallaria, but chiefly by the latter. The convallaria resembles a bell-shaped flower, supported upon a slender footstalk, by which it is attached to fixed objects. This slender footstalk is highly contractile, and winds round in a spiral manner, when the animal is alarmed, and thus withdraws it from danger. The division only takes place in the bell, which first increases in circumference, and begins to divide at its margin, the fissure gradually extending to its base; when the fissure is complete, one half is found perfect, and is destined to continue on the footstalk, and may therefore be regarded as the parent of the other, which is now attached by a slight connexion to the top of the footstalk by the side of the permanent bell, which is found to have cilia not only at its upper margin, but also around its base. It now becomes detached and loses the marginal cilia, retaining the basal ones, and thus it swims about: but it has not yet developed its footstalk; this it gradually puts forth, the adult stage is then acquired, and it becomes fixed to some foreign body, like the parent when it sprung. While, in its free condition, this animalcule assumes various modifications of form, and in these states has been described as so many distinct species; and it is by recent observations only that its real character has become known. The

above sketch will illustrate the progress detailed, and also show the new animalcule, after gaining its freedom, in three different forms.

There is still another mode of reproduction by division: it occurs in animalcules which appear, as the gonium, to consist of a number of globules, (sixteen in one species,) enclosed in a thin transparent envelope; the mass thus compounded divides in this species into four equal parts, each part containing one large and three smaller globules: After their separation from each other, these parts swim freely about in the water, and increase in the number of their constituent globules, to undergo a fresh division. In other species, the division is into still more numerous portions.

Fourthly. Some animalcules increase by division, by gemmules, and by eggs or spawn.

In the Kolpoda cucullus, Ehrenberg detected, most satisfactorily, the latter mode, and he describes the eggs, when excluded, as appearing in the form of a delicate mass resembling network.

No mode of reproduction is more wonderful than that of division, none so productive. It is wonderful, when we consider that each divided part has to assume all the organs of the perfect being, that these have therefore to become developed, and to assume their due form and situation. And as to productiveness, the Paramecium aurelia, well supplied with food, has been observed to divide once in twenty-four hours, so that, as Professor Jones observes, "in a fortnight, allowing the product of each division to multiply at the same rate, 16,384 animalcules would be produced from the same stock," and in four weeks the astonishing number of 268,435,456 new and distinct beings.

Now let us pause, to reflect upon the power of that God, who has created these creatures for our examination, and for our instruction; perhaps, though we know not in what, for our benefit. Their minuteness confounds us; their numbers overwhelm us; their habits surprise us; their history teems with wonders. Difficulties meet us at every step; and we are forced at length to confess that the work of God contains mysteries, which baffle the penetration of philosophy. M.

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Brush Turkey of Australia. Talegalla Lathami, Gould.

THE BRUSH TURKEY OF AUSTRALIA.

No portion of the globe contains animals so singular in their structure, as Australia; in no other region does the naturalist find beings so strangely organized, or so extraordinary in their habits. We need not offer proofs of this assertion; they will suggest themselves to the mind of every one who is acquainted with the ornithorhynchus, the echidna, the kangaroo, and the wombat. The truth, however, of the proposition, as far as regards habits, is strikingly exemplified in the history of two birds peculiar to Australia, and of which we are about to give the details.

The two birds to which we here allude, are the brush turkey of the colonists, called wee-lah by the aborigines, (Talegalla Lathami, Gould,) and the native pheasant of the colonists, called ngow or ngow-oo by the aborigines, (Leipoa ocellata, Gould.)

The first was originally described by Latham, under the name of the New Holland vulture; but subsequently he removed it from among the vultures, and placed it among the birds of the gallinaceous order to which it really APRIL, 1841.

belongs. The second is also a gallinaceous bird, and has been recently made known to science by that enterprising naturalist, Mr. Gould. It is from his magnificent work on the birds of Australia, which, from its expense, can only be in the hands of the few, that we derive our account.

The brush turkey, or, as Mr. Gould terms it, the wattled talegalla, inhabits various districts of New South Wales, from Cape Howe on the south to Moreton Bay on the north. In some places, where it was once common, it has now become rare; and we learn that the cedar cutters, and others who are in the constant habit of hunting through the brushes of Illawara and Maitland have nearly extirpated it from these localities. It is, however, still abundant in the dense brushes of the Manning and Clarence, and along the sides of the lower hills that branch off from the great range into the interior; on the Brezi range to the north of the Liverpool plains, and also on the hills on each side of the Samoi.

In its habits, the brush turkey is gregarious, associating in small flocks,

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which wander among the dense covert | labours of several; the same site appears to me from the great size, and the entire decomposition of the lower part, to be resorted to for several years in succession, the birds adding a fresh supply of materials previously to laying.

"The mode in which the materials composing these mounds are accumulated, is equally singular; the bird never using its beak, but always grasping a quantity in its foot, throwing it backwards to one common centre, and thus clearing the surface of the ground for considerable distance so completely, that scarcely a leaf or a blade of grass is left.

of the brush wood; and it is shy and
distrustful. It runs with great facility,
and from the nature of the localities it
frequents, easily eludes pursuit. One
of its greatest enemies is the dingo, or
wild dog; and when hard pressed by
this ferocious beast of prey, it springs
to the lower branch of a tree, and, by
a succession of leaps from branch to
branch, ascends to the top. Thew hole
flock act in concert, and having ascended
as high as they can, they either remain
perched in security, or fly to a distanta
spot, where the tangled brush wood
promises a more effectual concealment.
They are also in the habit of resorting
to the branches of trees, as a shelter
from the mid-day sun; and while thus
reposing, they offer a sure mark to the
sportsman, who may kill the whole
flock, for they will allow a succession
of shots to be fired, without moving,
or being roused from their lethargy.
It is by taking advantage of their mid-
day repose, that the colonists destroy
them in great numbers for the sake
of their flesh, which is extremely deli-
cate and tender, and is consequently in
high esteem.

While wandering through the brush, these birds utter a clucking noise; their food consists principally of berries and various seeds; and, like our common poultry, they dust themselves in the soft ground, making bare depressions in the spots which they frequent.

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"The heap being accumulated, and time allowed for a sufficient heat to be engendered, the eggs are deposited, not side by side, as is ordinarily the case, but planted at the distance of nine or twelve inches from each other, and buried at nearly an arm's depth, perfectly upright, with the large end upwards. They are covered up as they are laid, and allowed to remain until hatched. I have been credibly informed, both by natives and settlers living near their haunts, that it is not unusual to obtain nearly a bushel of eggs at one time from a single heap; and as they are delicious eating, they are eagerly sought after."

Some of the natives assured Mr. Gould, that the females are constantly in the neighbourhood of the heap, waiting for the time at which the hatching of the eggs takes place; and that they eco-frequently uncover and cover again the eggs, as if for the purpose of ascertaining their progress, or of assisting the young to liberate themselves from their imprisonment. Others, however, denied this, and stated that the eggs were altogether forsaken, the young being left to liberate themselves. Unfortunately, Mr. Gould was not in the districts inhabited by these birds during the breeding season; but he inclines to the latter statement, and thinks that from the great size of the egg, there is room for the young to become more fully developed, than in ordinary cases, and that they are hatched capable of taking care of themselves. In confirmation of this, he observes that, in searching for eggs in one of the mounds, he discovered the remains of a young bird, apparently just excluded from the shell. It was clothed, not with down as is usual, but with feathers, a proof, if

The most interesting and remarkable circumstance connected with the nomy of the brush turkey is, that it does not hatch its eggs by incubation, it does not sit upon them like other birds, not even occasionally or during the night, but forms for them an caleobion," in which they are hatched without the weary duties to which other birds are called by the laws of nature. The brush turkey, says Mr. Gould, "collects together an immense heap of decaying vegetable matter, as a depository for the eggs, and trusts to the heat engendered by the process of decomposition for the developement of the young. The heap employed for this purpose, is collected by the birds during several weeks previous to the period of laying; it varies in size from two to four cart loads, and is of a perfectly pyramidal form. The construction of the work is not the work of one pair of birds, but is effected by the united

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