The Zoophytes* are here in their glory. Such places as those I speak of are the very capitals of the zoophytic nation. Look at this great leaf of the fingered Tangle : see how its broad olive-brown expanse is covered with tiny forests of white branching threads, which spread and spread till they run off into the fingers of the much split leaf; and not only on one side, for the under surface is as densely clad with the shaggy burden as the upper; the smooth leathery tissue being covered with a network of creeping roots, branching and radiating everywhere, like the railways on Bradshaw's map.

This double forest is wholly composed of a single species, called Laomedea geniculata ; nay, I believe it is but one single individual. That is to say, the whole of these multitudinous ramified threads and stems, with their innumerable polypes,! have all extended by gradual though rapid growth from a single germ ; and all are connected even now, so that a common life pervades the whole. But we will look awhile at it in detail, till we have mastered its external features, and then I will tell you something of its history and economy.

With the unassisted eye we can discern plainly enough the outline and plan of this compound organism. Along the smooth and slippery surface of the olive weed runs a

From the Greek £u)oi'(zoon), an animal, and tpvrbv (phuton), aplant. A term applied to a large class of animals bearing 'polypes, and whose entire skeleton, called a polypar-y or polypidom, more or less resembles a plant or tree in its appearance and growth.

The term Cozlenterata is now substituted for this in systematic natural history. See Prof. Greene's excellent " Manual of the Anim. Kingd." ii. Lond. 1861.

t From the Greek 7to\vq (polus), many, and ttovq (pous), afoot. A low order of animals having numerous tentacles or feelers round the mouth, and often bearing a strong resemblance to flowers.

fine thread of pellucid white appearance, so firmly adherent that if you attempt to remove it with a needle's point, you find that you only tear either the leaf or the thread. The course is generally in a straight line, but does not ordinarily pursue the same direction far, commonly turning off with an abrupt angle at intervals of about an inch; and thus meandering in a zig-zag fashion, very irregularly, branching frequently, and uniting with a thread already formed, when the creeping one has to cross it.

Thus the basal network is formed; but, meanwhile, from every angle, and often from intermediate points, a free erect thread has shot up, like the stem of a tiny plant, to the height of an inch, rarely more ; not, however, straight, but with frequent zig-zag angles, whence the name geniculata, or " kneed." At every angle a slender branch is sent forth, pursuing the same direction as that of the joint from the summit of which it issued, and terminating in a tiny knob. In the angles of some of these branchlets are seated oblong vesicles, twice or thrice as large as the terminal knobs. And this is pretty well all that we can make out with the naked eye.

Cutting carefully off with scissors a narrow strip of the leaf, I drop it into the parallel-sided cell of glass half-filled with sea-water, and examine it first with a low power and afterwards with a higher. We now see that the creeping thread is a tube of horny substance, flattened on its under side, and that the erect stems and their branches are similar tubes, whose cavities are in free communication with that of the creeping root. The wall is thin, and perfectly transparent and colourless ; the whiteness of the whole being dependent on a soft medullary core of living jelly, which permeates the whole structure, on which the horny sheath is, as it were, moulded.

This medulla is pierced with a canal, through which a fluid circulates, carrying along numerous minute granules with a quivering, jerking motion; this is doubtless the nutrient fluid conveying the products of digestion to every part of the common structure.

Where the branches issue from the angles of the stem, the medulla, and consequently the horny sheath, is dilated into a knob; immediately above this there is a joint-like constriction in the tube, and the branch itself is insected by four or five such constrictions, so as to form as many rings. Its extremity then expands into an elegant cup or vase, of extreme tenuity and transparency, shaped like a wineglass, with the rim undivided, but so thin and subtle as to be seen with the greatest difficulty. These cups, or cells, are LAOilEDEA. each the proper habitation of a polype, which is nothing else but the termination (in this direction) of the living, growing, vascular pith. The latter becomes exceedingly attenuated, in order to pass through a very narrow orifice in the centre of a horny diaphragm, or sort of false bottom, which passes across the lower part of each cell. It then dilates into a soft, contractile animal, whose body—but look for yourself; for here, full in the field of the microscope, is one expanding in the highest vigour and beauty.

It is a long trumpet-shaped body of granular flesh, the mouth of which just reaches the brim of the cup, over which it spreads on all sides. From its margin spring some eighteen or twenty tentacles—the exact number

varying in different individuals—arranged in one or two close-set circles, like a crown. These organs, which, as you see, fall into elegant double curves, like the branches of a chandelier, are roughened with knobbed rings, something like the horns of a goat; this structure we will presently submit to more close examination.

In the midst of the space surrounded by the tentacular crown there is protruded, at the pleasure of the animal, a large, fleshy, funnel-shaped mouth, the lips of which are highly sensitive, continually changing their form; protruding, contracting, bending in upon themselves, now closing, now opening the mouth, and, as it were, testing the immediate vicinity, like a very delicate organ of some unknown sense.

The whole polype is much too minute for us to attempt, with any probability of success, the amputation of one of the tentacles with scissors. But by cutting off a polype, cell and all, and putting it into the compressorium, we may be able, by means of the graduated pressure, to flatten the whole, and thus discern the gnarled structure of the tentacles. A very high magnifying power is needed for this.

Here, then, we have one of the tentacles flattened between the glass plates,but still retainingits integrity. We find that the thickenings are similar in character to those of the tentacles of Sarsia,which we lately observed. They are, in fact, accu- TENTACLE OF LA01IEDEA ; flattened. mulations of cnidce, those peculiar weapons of power, which T shall presently describe in full; but here they are symmetrically arranged in single rows, each pointing upward and outward.

To return to the living specimen on the leaf : you see seated in the angles of the branches, here and there, elegant urn-shaped cells, larger than the polype cells, each with a sort of shoulder and a narrow neck. The common marrow passes from the joint into the bottom of these, and then extends through the centre till it reaches the mouth. In some of the urns this forms merely a slender column, expanding at the mouth; but in others it enlarges at irregular intervals into large knobs or masses of granular flesh, which are confusedly grouped together, eight or ten in one capsule. This latter is the most interesting condition; let us watch it.

While doing so, let me inform you that these urns are the reproductive organs ; and the fleshy masses are embryos of peculiar character, which are developed out. of the nutrient medulla. The largest of those now under observation is, as you see, moving, and slowly working its way out of its glassy prison. Two or three flexible finger-like bodies are protruding from the orifice of the urn, and more are joining them : we see they are tentacles, protruded in a loose bundle, just as the polype emerges from the cell.

It is a somewhat slow process; but at length the fleshy mass squeezes itself forth, as if pushed out by some contractile force behind; while we see the fluids, carryinggranules, run into the parts of the tentacles which are already free. The embryo is liberated.

For a few seconds it appears helpless, and falls through the water in a collapsed state, so that we cannot discern its proper form. It gives a spasmodic contraction or two, feeble at first, then more vigorous; the tentacles lengthen, the body expands, and—lo ! it is not a Polype, but a Medusa !

And now take your eye for a moment from the microscope, and glance at this glass jar, in which the oarweed with its colony of Zoophytes has been standing for a few hours. Hold it between your eye and the light; do you not see that the water is alive with tiny dancing atoms 1 Hundreds are there, playing and pumping through the fluid with a sort of napping motion, which, when you get one sidewise in clear view, will not fail to remind you of the flagging flight of some heavy-bodied, longwinged bird. These are the Medusa-shaped progeny of the Laomedea.

But let us return to the one of which we have just witnessed the birth, and which is still flapping to and fro in the narrow glass trough. You see a pellucid, colourless disk or umbrella of considerable thickness, about onesixtieth of an inch in diameter in its average state of expansion. Its substance has a reticular appearance, probably indicating its cellular texture. Internally, the disk rises to a blunt knob in the centre, whence four vessels diverge to opposite points of the margin. These form elevated ribs, the surface being gradually depressed from each to the centre of the interspace. Externally, the centre of the disk is produced into a fleshy peduncle, having a narrow neck, and then expanding into a sort of secondary disk, of a square form, with the angles rounded. This organ, which is capable of varied, precise, and energetic motions, corresponds to the peduncle of a true Medusa, the angles being the lips. These lips, which correspond in their direction to the four internal ridges, are very protrusile; and, when the little animal is active, are continually being thrust out in various directions, sometimes everted, but more commonly made to approach each other in different degrees ; sometimes one being bent-in towards the centre, sometimes all closing-up around a hollow interior. These four lobes, thus perpetually in motion, and changing within certain limits their form and their relation to each other, remind one of the lips or the tongues of more highly organised animals. The substance of this peduncle appears to be delicately granular ; but there is a very manifest tendency to a fibrous character in its texture, the fibres being directed from the exterior towards the interior, supposing the lobes to have their points in contact.

Let us now look at the margin of the disk. Here are attached twenty-four slender tentacles, six in each quadrant formed by the divergent ribs, or radiating canals. Each tentacle springs from a thickened bulb, which is imbedded in the margin of the disk ; it is evidently tubular, but the tube is not wider in the bulb than in the filament. The general surface is rough, with projecting points, which in some assume a very regular spinous -appearance, and the tentacle terminates in a blunt point. The discal part of the bulb is fringed with a row of minute bead-like spherules. Around the edge of the circumference •of the disk, on the exterior, are arranged eight beautiful and conspicuous vesicles, or organs for hearing. They are placed in pairs, those of each pair being approximate, and appropriated to each of the quadrants of the circle. Each of these organs consists of a transparent globe, not enveloped in the substance of the disk, but so free as to appear barely in contact with it: it contains a single otolithe, of high refractive power, placed, not in the centre, but towards the outer side. The inexperienced naturalist, on first seeing these organs, would unhesitatingly pronounce them eyes, and the otolithe, or ear-stone,* the crystalline lens. They are, however, pretty certainly, rudimentary organs of hearing; the crystalline globule or otolithe being capable of vibration within its vesicle. Their •exact counterparts are found in many of the smaller Medusae, as we lately saw in the Thcmmantias.

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