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green contents are arranged round double nuclei, on each side of the constriction; and at times (probably before the increase by cell-division takes place) dark-coloured particles, having a peculiar "swarming" motion, may be seen between each pair of nuclei. Perhaps in no plant can the processes of cell-division and conjugation be more readily traced.

Figs. 1 to 4 show the mode in which cell-division takes place. The constriction across the frustule

becomes wider, and a small protuberance appears between the two half cells, across which a wall of separation seems already to have been formed. The parts of this protuberance gradually enlarge, at first containing only the "swarming" particles; then assuming the form and colour of the corresponding half cells; and at length, when the growth is complete, separating into two perfect frustules. In these the process of cell-division is again repeated, so that the multiplication of these simple plants under favourable circumstances must be exceedingly rapid; though there is, doubtless, a limit beyond which the multiplication does not extend.

In conjugation two cells, which are near to one other, each divide at the constriction, and pour out their contents into one common mass (fig. 6) which is held together by a gelatinous envelope. This mass, which at first is of irregalar shape (figs. 6, 7), and contains small transparent, colourless globules (possibly of oil), gradually obtains a more regular form (fig. 8), and at length becomes a spherical sporange, convored with forked protuberances. (fig. 10^[1]).

The contents of the sporange at first seem to consist of irregular, rounded green masses. Afterwards these become either uniformly blended, or else increase so as to fill up the sporange, which then presents a dark green aspect. Subsequently the contents appear as a central, green mass, surrounded with purplish matter; and, being to some extent, less in bulk, make the surrounding cell-wall very apparent.

That the sporanges, after a time, break up and produce new plants is very evident; though it is difficult to detect when or how this takes place. A muss of cells (fig. 12) may, perhaps, be an early stage in their development; for such masses occur abundantly in the water in which the Cosmarium is kept, and bear a considerable likeness to the perfect frustules.J. S. Tute.

I think I am right when I say that very few persons know the great interest this little animal is capable of affording, except, of course, those who have cultivated its acquaintance by keeping it as a pet,—interest not only as regards its habits and mode of life during both summer and winter, but also as to the variety of food it requires, and the enormous quantity of that food which, for so small a creature, it will consume; together with the amusement produced by watching its innocent gambols during its hours of feeding.

The Dormouse is indeed, as described by Milne-Edwards, in his work on Natural History, a pretty little animal, with soft hair, velvety tail, ever tufted, with a lively look, having a strong analogy to the rat; it belongs to a genus of the Linnæan order Glires, and it inhabits temperate and warm countries, subsisting entirely on vegetable food. In Varro, De Re Rustica, we find that the art of rearing and fattening great numbers of this genus was practised in Roman villas, as a profitable article of rural economy; and again in Brotier, the last edition of Pliny, we read that the excessive demand of them for luxurious tables was increased by the foolish prohibitions of the censors and it is reported that they are still esteemed in modern Rome, being frequently sent as