“The exterior resemblance of these corpuscules to the Antherozoids of Vaucheria, justifies one in attributing to them analogous functions. When these antherozoids become free and diffused through the water, they reunite after a time round certain cellules, whose contents are organised like spores. They agitate the water near these cellules; they attach themselves to its walls, leaving it for an instant, then returning immediately. Finally, one of the corpuscles, approaching one of the openings existing in the membrane of the sporanges, it fixes itself there, and introduces its delicate beak. Sometimes the posterior part of its body becomes too large to pass with impunity; then we see it pushing itself on, but without relaxing the hold with its beak, contracting and making itself smaller. In short, it forces itself a passage and penetrates into the cavity of the sporange. At the same time other antherozoids penetrate in the same manner or by analogous methods. Three or four of these are often engaged at once in the same opening; the smallest pass without difficulty at the first attempt, and in their movement of translation with the liquid in which they swim in the bosom of the sporange, describe great circles, and constitute an extremely curious phenomenon. After a few moments the Sporange may contain more than twenty of these antherozoids, Which agitate themselves round the young spores. These are, as T have stated above, small soft spheroids, more or less completely filled with chlorophyle, and enveloped in a mucous bed, having, however, none of the characters of a cellulose membrane. The Spermatozoids throw themselves one spore upon another, as if omic electric attracted and repulsed them alternately, and that so rapidly that the eye can scarely follow their movement. They are often observed to move with the same agility from one end of the sporange to the other, while the agitation of their vibratile cells impresses upon the spores a slow movement of rotation. I have Seen the antherozoids agitate themselves confusedly in the cavity of the Sporange during more than two hours. Their movement omes slower and slower by degrees, and they finish by attaching themselves to the surface of the young spores. We can then See one or two fix themselves by the cilia and the beak upon “ach of these bodies, dwelling as if implanted there, oscillating

there for some time; then finally they become quite immovable, and attach themselves in all their length upon the spore. Their body loses its form; it is no longer a mere mucous drop, of which a part seems to be absorbed. by the spore. The primordeal spore, now fecundated, soon becomes covered with a true eSphosropleas cellular membrane, as represented in Fig. 501.” When these spores are prepared to germinate, their contents are subjected to many modifications. They become granulated, assuming a sombre tint of reddish brown, and e transparent circle shows itself in the centre. The reddish matter frequently ‘ assumes a greenish tint before germination. This change °

a b c

Fig. 302. Spores of Sphzroplea in course of germination.

colour proceeds slowly and step by step from the exterior of the spore towards the centre of its cavity, and the plastic contents finally separate, first into two, then into four, and ultimately inte a much greater number of parts (Fig. 302, a, 4, c), which rupture their double envelopes and spread themselves freely in the wate? like so many zoospores. The form of these zoospores is as uncertain as their size and»

colour. During more than an hour these corpuscles, farnished with two cilia to their beak, agitate themselves by a slow jerking movement, interrupted from time to time with long pauses, ant it almost seems as if they had lost their power of movement when, after many hours of immobility, they suddenly resume their motion. When these zoospores begin to germinate they elongate themselves more and more, in a spindle-like form, swelling in the middle, as in Fig. 303, a, b,c, d,e, f. In a short time the little plant, hitherto formed of a single cell, separates into two equal compartments; then, successively, into a great number of cells, at the cost of, and in proportion to their size, becoming finally a yours Spheeroplea.

Such is a brief history of S;/eroplea annulina, in which the descriptions of M. Cohn are only slightly abbreviated. The strange details give birth to feelings of profound admiration in the naturalist and thinker. Here are individuals placed ai the bottom of the vegetable scale a i which are reproduced by the emission of | germs gifted with a movement of their ¥* own, and seemingly guided in their evolutions by a true kind of instinct. Looking at these voluntary movements 80 apparent in the younger generations of an inferior vegetable, one is drawn, with the German naturalist, to consider them as animals, which, by holding themselves immovable, and attaching them- Selves to some object, become vegetables. ut how much do these facts overthrow the notions generally entertained of the distinctions between animals and Plants! {n order to know in what life consists, it is not sufficient to contemplate creatures of the higher organ- ve. isation only;the whole series of creation must be contemplated, from man down to the humble spheroplea.

II. Fucacez.

The Seaweeds closely resemble Confervaces both in structure and local habitat. They differ in their mode of reproduction, the organs appearing as little green warts on the outside of the plant, myested by a thin membrane enclosing the sporules; while the antheridia have a spiral filament. Some of them are used as food, as Alaria Esculenta, and £ucus vesciculosus, which are eaten by the inhabitants of Scotland and {reland, and the natives of the shores - the Pacific. They have also been extensively employed for industrial purposes, both in our own and other countries, in the manufacture of kelp, glass, and especially iodine, which is extracted

from many species. The Fucacce are distinguished from all other seaweeds by a remarkable characteristic, namely, the position of their spores within little hollows sunk in the substance of the plant, and communicating with the surface by a pore.

Dr. Lindley divides the order of Fucacese into the three following sub-orders, each distinguished by their own peculiarities:—

Frona mono,nO or pleis, sephonous, H without ‘) Including: Hydrogastrum and

I, VAUCHERLE. =bark, theA utricles forming a lateral- branchlet,. paSell Dasy 7sanggpoa |Ectocarpus,or 03, e€ upper joint, sometimes fro west. 2 the Spacelaria, the Frond polysiphonous, barked and jointed, neluding ‘. {. q } ¢ Léeha £. A i Dictyosiphon, Laminaria, and Sper I.. H ULYSEREAZ lor in heaps. } achnus.

Frond polysiphonous, often bladdery, vesi-; cles seated in hollow conceptacles formed of Including the Lemanea, Phe Ill. Fuces, a folding-in. of the fold, pierced by a spore }Cystoceira, Sargassum, surrounded by flock; conceptacles scattered | naria, and Scirococcus. or collected upou a receptacle.

Two species of Sargassum, S. vulyare and 8S. vacciferum, are frequently found on our shores as far north as the mouth of the Clyde and the west coast of Scotland; but they are mere waifs and strays cast with other tropical productions on our shores- They are the “Gulf-weed” which form floating meadows an the midst of the ocean. ‘ Midway the Atlantic,” says Maury, his of the Sea,” p. 88, “in the triangular space ‘« Physical Geography between the Azores, Canaries, and the Cape de Verd Islands, 38 the great Sargasso Sea, covering an area equal in extent to = Mississippi Valley; it is so thickly matted over with the 5 weed that the speed of vessels passing through it is often retarded. When the companions of Columbus saw it, they thought it marked the limits of navigation, and became alarmed. To the eye, at® little distance, it seems substantial enough to walk upon.” ety reproductive bodies of these plants are in the beginning little yoo: placed close over e by a very thin membrane, ike bodies, invested inner sac filled with green granules. The spores are external;tha of a vescicle upon which they on the surface is, they are inserted are generated.

VAUCHERIA. Tufts of Vaucheria are formed of a network of cylindrical fila ments, branching and continuous, enclosing green granules and a colourless mucilage. This small plant, common enough 1 marshy places, is rendered very remarkable by its diverse

of reproduction. It has been the subject of most interesting and minute investigations made by M. Thuret and Von Pringsheim. Its reproductive spores are, as we shall see, gifted at one period of their existence with a true movement, and it may actually be said to walk. This very remarkable fact shows how difficult it sometimes is to establish precise differences between plants and animals, and to define absolutely the limits of what are sometimes called the kingdoms of nature.;

The extremity of the filaments of this Fuci are swollen into a club-like form, and the green matter is condensed there until a 6 c d e

Fig. 304, Transformation ot Vaucheria. Fig. 305. Spore of Vaucheria escaping. it assumes a blackish tint. In Fig. 304 are represented the

= Place. According to M. Thuret, the granules separate emselves slowly, the one from the other, towards the base of the like Swelling, leaving there a vacant space. The granules how ap Proach each other again, and once more forma junction. But then a great change takes place, for this singular operation

seems to determine the separation of the motler plant from the reproductive body or spore. Henceforth the spore is inves with a proper membrane, and possesses a distinct organisation. This is the moment when the crisis approaches. ‘The upper extremity of the spore is ruptured (Fig. 305); at the same time it begins to turn on its axis so completely that the granules contained may be observed passing rapidly from right to left, and from left to right, as if they moved in the interior of a transparent cylinder. The narrow opening by which the spore secks its egress produces a very marked state of strangulation. In a few moments it succeeds in disengaging itself and throws itself into the water.

Pam Once detached from the mother, the individual spore ‘f= now, as represented in Fig. 306, coniinues to turn upon 463.4) itself unceasingly, but with a very irregular motion, Its 5 / movement being now quick or slow in one direction and @/ now inanother. Generally it gains the edge of the object-rig. 306, glass on which the observation is being made as ifif sought to escape from its prison-house. Sometimes i” motion is arrested for an instant, and immediaicly it resumes its more active career. ce The whole surface of the spore is covered wit» vertibratal cilia, ig. 307, which, however, are quite invisible from the rapidity of their motion. In order to 8

| effect of this application is very remarkable.

/ opium reduces the movements of ihe spores of the 1? Vaucheria so as to admit of the play of the organ being quite perceptible. The iodine arresis them suddenly, and makes their motion more perceptible

Fig. 907, Spore with 40m the suddenness of their arrest. ‘The +; iteCitie, employed by M. Thuret contained only on? thousandth part of iodine. of

This gentleman has succeeded in following the movements a spore of Vaucheria in water during more than two our When the cilia finally cease to move, the spores remain immovable and soon begin to germinate (Fig. 308), giving birth to 4 Fuci, a new Vaucheria.

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