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regular succession in the same plane, which forms a right angle to the arrangement of the cells. Each of the capsules or vesicles is a tall, vase-like, transparent body, considerably larger than a cell, but closely resembling it, except that its summit is abruptly narrowed to a short rim, like a pitcher. One of these organs is represented in fig. b.

The common nutrient flesh permeates the capsule as it does a cell, and developes therein a very peculiar embryo. When somewhat matured, the permeating tube is seen swollen out into separate ovate sacs, ten or more in number, each of which contains several embryos. Those nearest the mouth of the vesicle are first developed, and escape successively, by slowly emerging from the pitcher-like rim. Fig. c represents a vesicle much magnified, with its included embryos in various degrees of maturity, and one in the act of escaping. The appearance of the tiny creature, when it finds itself at liberty, is most surprising and interesting, especially when, from a crowded forest of polypes, the embryos are escaping by thousands. Mr. Peach, who first observed them, thus describes the scene he saw. Having, on the 19th of February, placed a specimen of Laomedea dichotoma in a large glass of sea-water, he found, a day or two after, that the water appeared muddy, an appearance caused by myriads of moving objects, that resembled umbrellas without handles, or very wide and short hand-bells. "I took,” says this agreeable observer, "a small quantity of the water, and placed it under the microscope, when thousands of the objects were sporting about in all directions, moving at a rapid rate by the ciliary appendages on their rim. All at once they would withdraw their cilia, and the handlelike appendage on the back, and become a mere speck; and after resting a short time they would again throw out their cilia and appendage, and round they went waltzing with each other. It was perfectly astonishing in this crowded

assembly to find that they very seldom came into collision; and if so, how soon matters were again accommodated. They continued active up to the 2d of March, when I lost them as if by magic. I fancied they might have been the young of worms; therefore, I took the Laomedea, washed it, took fresh sea-water and filtered it through three or four folds of fine linen, and placed the specimen in this: the next morning I had a still more innumerable host of these delightful things. They assume various positions, and when in the water they remind me of thousands of parachutes thrown from a balloon, descending in various states of expansion.”

The writer of these papers has had an opportunity of confirming and extending the observations of Mr. Peach. It is easy to find the minute, sylph-like creatures, for all that is needful is to place in a vessel of sea-water a frond of seaweed studded with the zoophyte, and in a few hours scores or hundreds will be seen, even with the naked eye, playing and dancing about in the most amusing manner. Fig. d represents the embryo, very highly magnified.

In structure the tiny animal, which, though just born of a stationary zoophyte, is now swimming at will in a sprightly manner through the free water, is evidently a Medusa; in all essential particulars being the very counterpart of one of those exquisitely delicate animals which Professor Forbes has so beautifully described and portrayed in his "Monograph of the British Naked-eyed Medusa." It consists of an umbrella-shaped disk of translucent jelly, the diameter of which is about th of an inch. Four vessels cross the disk at right angles, and from the centre of union there springs a fleshy peduncle, with a sort of neck, capable of many varied motions and many alterations of form. The margin of the disk carries twenty-four slender tentacles, exactly corresponding to those of the parent polype, and essentially to those of the Hydra; being studded

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with warts, which analogy pronounces to be aggregations of barb-bearing capsules, instruments for arresting and killing prey. At the bases of the tentacles, arranged at certain definite points on the margin of the disk, are placed eight beautiful organs, which are doubtless the seats of a special sense. 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. In its interior is borne a smaller globule or lens, of high refractive power, placed a little towards the outer side. Almost every one, on first beholding these organs, would unhesitatingly pronounce them eyes, and so they are considered by some eminent physiologists. Others, however, consider them to bear a closer analogy to our organs of hearing; the crystalline globule (or otolithe) being, as it is stated, capable of vibration within its vesicle. Whatever they be, the same organs are found in the same form, in that class of animals just alluded to, the jelly-fishes or medusæ.

The disk is endowed with an energetic power of contraction, by which the margin is diminished, exactly like that of a medusa in swimming; and the tentacles have also the power of individual motion, though in general this is languid, their rapid flapping being the effect of the contraction and expansion of the disk just mentioned, producing a quick involution and evolution of the margin, and carrying the tentacles with it. Occasionally, however, all the tentacles are strongly brought together at their tips, with a twitching, grasping action, like that of fingers, which is certainly independent of the disk.

The phenomena, of which an example has been given in this paper, have almost as greatly startled the philosophers of our age, as those connected with the reproduction of the Hydra astonished our ancestors a century ago. As in the former case, they were disbelieved, denied, ridiculed, confirmed,

believed, wondered at, and at length have found a place among the recognised laws of organic life, as the Law of the Alternation of Generations. When we come to speak of the Medusæ as a class, we shall have occasion to revert to the topic again; for the present we may state, that the order described is found to prevail among many species and genera of the marine polypes. That order is briefly as follows:The polype, a fixed and rooted animal, increases its own individual life for awhile by putting forth a succession of budding heads, but at a certain period gives birth to a number of beings that bear no resemblance to itself in form or habit, but are, to all intents and purposes, free swimming medusæ. Each of these, after pursuing its giddy course for a time, produces a number of eggs, which change into active animals having the closest resemblance to Infusoria. Each of these latter presently becomes stationary, and affixed to some foreign body, along which it creeps as a root-thread, shooting up tubular and celled polypes, as described in the early part of this paper.

It is evident that this is a very different thing from the metamorphosis which takes place in Insects and Crustacea, where it is but one individual passing through a succession of forms, by casting off a succession of garments that concealed, and, as it were, masked the ultimate form. The butterfly is actually contained within the caterpillar, and can be demonstrated there by a skilful anatomist. In this case, however, there are distinct births, producing in a definite order beings of two forms, the one never producing its image directly, but only with the interposition of a generation widely diverse from it. Hence, to use the striking though homely illustration of one of the first propounders of this law, any one individual is not at all like its mother or its daughter, but exactly resembles its grandmother or its granddaughter. P. H. G.

THE CHEQUE AND THE COUNTERFOIL.

A LESSON IN THE CHRISTIAN EVIDENCE.

COMING home a ship's company describes a remarkable scene which it has witnessed in the course of its wanderings. Discredited by some and believed by others, the deponents adhere to their statement with wonderful tenacity; nor can imprisonment and torture induce them to alter a single iota. After they are dead, and when all evidence is converging towards the truth of their story, many regret that they can no longer see and cross-question the original narrators. However, it turns out that in a public collection are sundry pictures containing an elaborate representation of the controverted incident, and believed to be the work of some of the spectators, or exact fac-similes from their originals. In settling the dispute, it is obvious that great interest will attach to these drawings, and it will be a matter of the utmost moment to ascertain their trustworthiness. Are they not modern forgeries? Do they contain no fatal incongruities? no anachronism in costume? no solecism in the landscape, or the objects which people it? and are they not flagrant copies the one from the other,—all four the same cunning fable in so many different disguises?

No, says the artist: they are not modern. They are as old as the time they profess. Their transmission is straightforward and abundantly established; and, even though there were no other proof, I know their antiquity from their style, and from the pigments and vehicles employed in their production.

No, say the physical geographer and the antiquary: they are true to the given time and place. That is the exact aspect of the country, and those are its characteristic