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of its ungrateful guest, for, though half of its young embryos may be devoured, it glides along with as swift and as majestic a course as ever; nor are the vibrations of its cilia intermitted, for any floating atoms that lie in its track are hurled away with impetuosity the moment they come within reach of this living whirlpool.

In some spheres we find eggs with Notommatæ; in some, eggs alone. Perhaps the parasite is always hatched in a parent Volvox, but the embryo globe is probably entered from without, and the Notommata is then expelled with it. The Notommato frequently eat their way out, and swim at freedom. Observing one, large with a nearly matured egg, in the globe of a small Volvox, I opened the latter with a fine needle, and freed the Notommata. This I placed in clear water, and added several Volvoces of various ages, taking care that none contained a parasite. I then watched its proceedings, to see if it would enter any one of the globes, but though in the course of its swift and headlong rotation it now and then came into contact with a globe, and would arrest its career to play over its surface, and even to nibble at it, it would presently dart away again, not entering one in the lapse of several hours. In the course of this time it deposited its egg loose in the water, which probably it would not have done had I left it to follow the dictates of its instinct.

For further details of the economy of this interesting creature I must refer to a paper of my own in the Transactions of the Microscopical Society of London for 1851.

EXPLANATION OF THE ILLUSTRATIONS. Plate XIX.-Fig. a represents Eosphora aurita, seen from the back, the ear

like lobes evolved, in the act of swimming. Fig. b represents the same animal, seen from the side, in the

position assumed in marching and feeding. Both figures are magnified about 250 diameters. From the life.

[merged small][graphic][graphic][merged small]

ON THE MORPHOLOGY OF VINCA MINOR

(SMALL PERIWINKLE).

BY JAMES BUCKMAN, F.L.S., F.G.S., ETC., PROFESSOR OF BOTANY

AND GEOLOGY.

TIME was when the collecting botanist almost avoided all

1 specimens of plants that were not typical in form; but since the immortal Goëthe propounded his remarkable morphological views, the aberrations of form assumed by some plants under extraordinary circumstances have been carefully inquired into, and their teachings made to explain the theories of plant structure-vegetable comparative anatomy_which knowledge is the very foundation of correct and philosophical classification.

Viewed in this light, examples of plants which were once set aside as monsters, are now carefully studied by the philosophical botanist, and as these often occur unexpectedly, I purpose from time to time to offer the readers of the POPULAR SCIENCE Review some illustrations of the more remarkable examples of morphological changes which have as yet come before me, or which may hereafter reward my search.

Now, in following out this plan no very lengthened description will be required, because even the student will at once recognise the meanings of the drawings; when, however, we have a tolerable series of cases before us, it may perhaps be well to recur to them, in illustration and elucidation of the remarkable views and generalisations such objects cannot fail to establish in the philosophic mind.

Our first specimen then is that of the Vinca minor (the Lesser Periwinkle). Plate XX., fig. 1, is a magnified drawing of a flower only partially expanded; in this the petals will be seen to be united into a tube, which has been opened to expose the curious columnar pistil and the five remarkable stamens. Here the style, of most elegant form, is surmounted by a stigma which is externally covered with fine bristle-like hairs, so pointing in every direction that, like a modern bristle door-mat, it is certain to sweep off whatever it may come near. Now, in the unexpanded flower the five two-lobed anthers converge over the top of this stigma; but as the flower opens, and is exposed to heat and sunlight, the anthers burst; and simultaneously

with this the column or style of the pistil elongates, and in its upward progress effectually sweeps off the liberated pollen (a 1), and thus the office of fertilization is brought about.

Figs. 2 and 3 are illustrations of a monstrous change in these simple arrangements. In these the petals have increased beyond the normal number of five, to ten; they are not united into a tube by their claws, but are separate and distinct. Of these, half are distinct petals, as fig. 4; and alternating with these, and forming an inner whorl, will be found stameniferous petals, as fig. 3a, and figs. 5 and 6.

In some examples of these monstrous flowers, enlarged stamens may be seen, as fig. 7; in which case the pistil is found usually more or less perfect, and the petals not wholly, but only partially free : here fertilization is possible, but there can be but little doubt that the resulting seed, on cultivation, would bring about the more complete change of form as represented in figs. 2 and 3. In this latter the pistil is abortive, consisting only of a small point representative of the style, and of course the seeds are not developed.

Illustrations of the above may be found in what is called the Double Periwinkle planted on most rockeries, and about the “wilderness," especially of our older gardens; and they may be viewed by the tyro in botany as objects of great interest, illustrating the fact that what was once called a monopetalous corolla is after all composed of five petals united at their base by cementation, whilst here the stamens may be viewed as metamorphosed petals.

EXPLANATION OF PLATE XX.

Fig. 1. An opened flower of Vinca minor showing the pistil just before it

pushes through the stamens by elongation.
Fig. la. Pollen of ditto, 300 diameters.
Figs. 2 & 3. Metamorphosed flowers, each with ten distinct petals.
Fig. 4. A separated petal.
Figs. 5 & 6. Petaloid Stamens.
Fig. 7. A true stamen.

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